Edit excel from python

Watch Now This tutorial has a related video course created by the Real Python team. Watch it together with the written tutorial to deepen your understanding: Editing Excel Spreadsheets in Python With openpyxl

Excel spreadsheets are one of those things you might have to deal with at some point. Either it’s because your boss loves them or because marketing needs them, you might have to learn how to work with spreadsheets, and that’s when knowing openpyxl comes in handy!

Spreadsheets are a very intuitive and user-friendly way to manipulate large datasets without any prior technical background. That’s why they’re still so commonly used today.

In this article, you’ll learn how to use openpyxl to:

  • Manipulate Excel spreadsheets with confidence
  • Extract information from spreadsheets
  • Create simple or more complex spreadsheets, including adding styles, charts, and so on

This article is written for intermediate developers who have a pretty good knowledge of Python data structures, such as dicts and lists, but also feel comfortable around OOP and more intermediate level topics.

Before You Begin

If you ever get asked to extract some data from a database or log file into an Excel spreadsheet, or if you often have to convert an Excel spreadsheet into some more usable programmatic form, then this tutorial is perfect for you. Let’s jump into the openpyxl caravan!

Practical Use Cases

First things first, when would you need to use a package like openpyxl in a real-world scenario? You’ll see a few examples below, but really, there are hundreds of possible scenarios where this knowledge could come in handy.

Importing New Products Into a Database

You are responsible for tech in an online store company, and your boss doesn’t want to pay for a cool and expensive CMS system.

Every time they want to add new products to the online store, they come to you with an Excel spreadsheet with a few hundred rows and, for each of them, you have the product name, description, price, and so forth.

Now, to import the data, you’ll have to iterate over each spreadsheet row and add each product to the online store.

Exporting Database Data Into a Spreadsheet

Say you have a Database table where you record all your users’ information, including name, phone number, email address, and so forth.

Now, the Marketing team wants to contact all users to give them some discounted offer or promotion. However, they don’t have access to the Database, or they don’t know how to use SQL to extract that information easily.

What can you do to help? Well, you can make a quick script using openpyxl that iterates over every single User record and puts all the essential information into an Excel spreadsheet.

That’s gonna earn you an extra slice of cake at your company’s next birthday party!

Appending Information to an Existing Spreadsheet

You may also have to open a spreadsheet, read the information in it and, according to some business logic, append more data to it.

For example, using the online store scenario again, say you get an Excel spreadsheet with a list of users and you need to append to each row the total amount they’ve spent in your store.

This data is in the Database and, in order to do this, you have to read the spreadsheet, iterate through each row, fetch the total amount spent from the Database and then write back to the spreadsheet.

Not a problem for openpyxl!

Learning Some Basic Excel Terminology

Here’s a quick list of basic terms you’ll see when you’re working with Excel spreadsheets:

Term Explanation
Spreadsheet or Workbook A Spreadsheet is the main file you are creating or working with.
Worksheet or Sheet A Sheet is used to split different kinds of content within the same spreadsheet. A Spreadsheet can have one or more Sheets.
Column A Column is a vertical line, and it’s represented by an uppercase letter: A.
Row A Row is a horizontal line, and it’s represented by a number: 1.
Cell A Cell is a combination of Column and Row, represented by both an uppercase letter and a number: A1.

Getting Started With openpyxl

Now that you’re aware of the benefits of a tool like openpyxl, let’s get down to it and start by installing the package. For this tutorial, you should use Python 3.7 and openpyxl 2.6.2. To install the package, you can do the following:

After you install the package, you should be able to create a super simple spreadsheet with the following code:

from openpyxl import Workbook

workbook = Workbook()
sheet = workbook.active

sheet["A1"] = "hello"
sheet["B1"] = "world!"

workbook.save(filename="hello_world.xlsx")

The code above should create a file called hello_world.xlsx in the folder you are using to run the code. If you open that file with Excel you should see something like this:

A Simple Hello World Spreadsheet

Woohoo, your first spreadsheet created!

Reading Excel Spreadsheets With openpyxl

Let’s start with the most essential thing one can do with a spreadsheet: read it.

You’ll go from a straightforward approach to reading a spreadsheet to more complex examples where you read the data and convert it into more useful Python structures.

Dataset for This Tutorial

Before you dive deep into some code examples, you should download this sample dataset and store it somewhere as sample.xlsx:

This is one of the datasets you’ll be using throughout this tutorial, and it’s a spreadsheet with a sample of real data from Amazon’s online product reviews. This dataset is only a tiny fraction of what Amazon provides, but for testing purposes, it’s more than enough.

A Simple Approach to Reading an Excel Spreadsheet

Finally, let’s start reading some spreadsheets! To begin with, open our sample spreadsheet:

>>>

>>> from openpyxl import load_workbook
>>> workbook = load_workbook(filename="sample.xlsx")
>>> workbook.sheetnames
['Sheet 1']

>>> sheet = workbook.active
>>> sheet
<Worksheet "Sheet 1">

>>> sheet.title
'Sheet 1'

In the code above, you first open the spreadsheet sample.xlsx using load_workbook(), and then you can use workbook.sheetnames to see all the sheets you have available to work with. After that, workbook.active selects the first available sheet and, in this case, you can see that it selects Sheet 1 automatically. Using these methods is the default way of opening a spreadsheet, and you’ll see it many times during this tutorial.

Now, after opening a spreadsheet, you can easily retrieve data from it like this:

>>>

>>> sheet["A1"]
<Cell 'Sheet 1'.A1>

>>> sheet["A1"].value
'marketplace'

>>> sheet["F10"].value
"G-Shock Men's Grey Sport Watch"

To return the actual value of a cell, you need to do .value. Otherwise, you’ll get the main Cell object. You can also use the method .cell() to retrieve a cell using index notation. Remember to add .value to get the actual value and not a Cell object:

>>>

>>> sheet.cell(row=10, column=6)
<Cell 'Sheet 1'.F10>

>>> sheet.cell(row=10, column=6).value
"G-Shock Men's Grey Sport Watch"

You can see that the results returned are the same, no matter which way you decide to go with. However, in this tutorial, you’ll be mostly using the first approach: ["A1"].

The above shows you the quickest way to open a spreadsheet. However, you can pass additional parameters to change the way a spreadsheet is loaded.

Additional Reading Options

There are a few arguments you can pass to load_workbook() that change the way a spreadsheet is loaded. The most important ones are the following two Booleans:

  1. read_only loads a spreadsheet in read-only mode allowing you to open very large Excel files.
  2. data_only ignores loading formulas and instead loads only the resulting values.

Importing Data From a Spreadsheet

Now that you’ve learned the basics about loading a spreadsheet, it’s about time you get to the fun part: the iteration and actual usage of the values within the spreadsheet.

This section is where you’ll learn all the different ways you can iterate through the data, but also how to convert that data into something usable and, more importantly, how to do it in a Pythonic way.

Iterating Through the Data

There are a few different ways you can iterate through the data depending on your needs.

You can slice the data with a combination of columns and rows:

>>>

>>> sheet["A1:C2"]
((<Cell 'Sheet 1'.A1>, <Cell 'Sheet 1'.B1>, <Cell 'Sheet 1'.C1>),
 (<Cell 'Sheet 1'.A2>, <Cell 'Sheet 1'.B2>, <Cell 'Sheet 1'.C2>))

You can get ranges of rows or columns:

>>>

>>> # Get all cells from column A
>>> sheet["A"]
(<Cell 'Sheet 1'.A1>,
 <Cell 'Sheet 1'.A2>,
 ...
 <Cell 'Sheet 1'.A99>,
 <Cell 'Sheet 1'.A100>)

>>> # Get all cells for a range of columns
>>> sheet["A:B"]
((<Cell 'Sheet 1'.A1>,
  <Cell 'Sheet 1'.A2>,
  ...
  <Cell 'Sheet 1'.A99>,
  <Cell 'Sheet 1'.A100>),
 (<Cell 'Sheet 1'.B1>,
  <Cell 'Sheet 1'.B2>,
  ...
  <Cell 'Sheet 1'.B99>,
  <Cell 'Sheet 1'.B100>))

>>> # Get all cells from row 5
>>> sheet[5]
(<Cell 'Sheet 1'.A5>,
 <Cell 'Sheet 1'.B5>,
 ...
 <Cell 'Sheet 1'.N5>,
 <Cell 'Sheet 1'.O5>)

>>> # Get all cells for a range of rows
>>> sheet[5:6]
((<Cell 'Sheet 1'.A5>,
  <Cell 'Sheet 1'.B5>,
  ...
  <Cell 'Sheet 1'.N5>,
  <Cell 'Sheet 1'.O5>),
 (<Cell 'Sheet 1'.A6>,
  <Cell 'Sheet 1'.B6>,
  ...
  <Cell 'Sheet 1'.N6>,
  <Cell 'Sheet 1'.O6>))

You’ll notice that all of the above examples return a tuple. If you want to refresh your memory on how to handle tuples in Python, check out the article on Lists and Tuples in Python.

There are also multiple ways of using normal Python generators to go through the data. The main methods you can use to achieve this are:

  • .iter_rows()
  • .iter_cols()

Both methods can receive the following arguments:

  • min_row
  • max_row
  • min_col
  • max_col

These arguments are used to set boundaries for the iteration:

>>>

>>> for row in sheet.iter_rows(min_row=1,
...                            max_row=2,
...                            min_col=1,
...                            max_col=3):
...     print(row)
(<Cell 'Sheet 1'.A1>, <Cell 'Sheet 1'.B1>, <Cell 'Sheet 1'.C1>)
(<Cell 'Sheet 1'.A2>, <Cell 'Sheet 1'.B2>, <Cell 'Sheet 1'.C2>)


>>> for column in sheet.iter_cols(min_row=1,
...                               max_row=2,
...                               min_col=1,
...                               max_col=3):
...     print(column)
(<Cell 'Sheet 1'.A1>, <Cell 'Sheet 1'.A2>)
(<Cell 'Sheet 1'.B1>, <Cell 'Sheet 1'.B2>)
(<Cell 'Sheet 1'.C1>, <Cell 'Sheet 1'.C2>)

You’ll notice that in the first example, when iterating through the rows using .iter_rows(), you get one tuple element per row selected. While when using .iter_cols() and iterating through columns, you’ll get one tuple per column instead.

One additional argument you can pass to both methods is the Boolean values_only. When it’s set to True, the values of the cell are returned, instead of the Cell object:

>>>

>>> for value in sheet.iter_rows(min_row=1,
...                              max_row=2,
...                              min_col=1,
...                              max_col=3,
...                              values_only=True):
...     print(value)
('marketplace', 'customer_id', 'review_id')
('US', 3653882, 'R3O9SGZBVQBV76')

If you want to iterate through the whole dataset, then you can also use the attributes .rows or .columns directly, which are shortcuts to using .iter_rows() and .iter_cols() without any arguments:

>>>

>>> for row in sheet.rows:
...     print(row)
(<Cell 'Sheet 1'.A1>, <Cell 'Sheet 1'.B1>, <Cell 'Sheet 1'.C1>
...
<Cell 'Sheet 1'.M100>, <Cell 'Sheet 1'.N100>, <Cell 'Sheet 1'.O100>)

These shortcuts are very useful when you’re iterating through the whole dataset.

Manipulate Data Using Python’s Default Data Structures

Now that you know the basics of iterating through the data in a workbook, let’s look at smart ways of converting that data into Python structures.

As you saw earlier, the result from all iterations comes in the form of tuples. However, since a tuple is nothing more than an immutable list, you can easily access its data and transform it into other structures.

For example, say you want to extract product information from the sample.xlsx spreadsheet and into a dictionary where each key is a product ID.

A straightforward way to do this is to iterate over all the rows, pick the columns you know are related to product information, and then store that in a dictionary. Let’s code this out!

First of all, have a look at the headers and see what information you care most about:

>>>

>>> for value in sheet.iter_rows(min_row=1,
...                              max_row=1,
...                              values_only=True):
...     print(value)
('marketplace', 'customer_id', 'review_id', 'product_id', ...)

This code returns a list of all the column names you have in the spreadsheet. To start, grab the columns with names:

  • product_id
  • product_parent
  • product_title
  • product_category

Lucky for you, the columns you need are all next to each other so you can use the min_column and max_column to easily get the data you want:

>>>

>>> for value in sheet.iter_rows(min_row=2,
...                              min_col=4,
...                              max_col=7,
...                              values_only=True):
...     print(value)
('B00FALQ1ZC', 937001370, 'Invicta Women's 15150 "Angel" 18k Yellow...)
('B00D3RGO20', 484010722, "Kenneth Cole New York Women's KC4944...)
...

Nice! Now that you know how to get all the important product information you need, let’s put that data into a dictionary:

import json
from openpyxl import load_workbook

workbook = load_workbook(filename="sample.xlsx")
sheet = workbook.active

products = {}

# Using the values_only because you want to return the cells' values
for row in sheet.iter_rows(min_row=2,
                           min_col=4,
                           max_col=7,
                           values_only=True):
    product_id = row[0]
    product = {
        "parent": row[1],
        "title": row[2],
        "category": row[3]
    }
    products[product_id] = product

# Using json here to be able to format the output for displaying later
print(json.dumps(products))

The code above returns a JSON similar to this:

{
  "B00FALQ1ZC": {
    "parent": 937001370,
    "title": "Invicta Women's 15150 ...",
    "category": "Watches"
  },
  "B00D3RGO20": {
    "parent": 484010722,
    "title": "Kenneth Cole New York ...",
    "category": "Watches"
  }
}

Here you can see that the output is trimmed to 2 products only, but if you run the script as it is, then you should get 98 products.

Convert Data Into Python Classes

To finalize the reading section of this tutorial, let’s dive into Python classes and see how you could improve on the example above and better structure the data.

For this, you’ll be using the new Python Data Classes that are available from Python 3.7. If you’re using an older version of Python, then you can use the default Classes instead.

So, first things first, let’s look at the data you have and decide what you want to store and how you want to store it.

As you saw right at the start, this data comes from Amazon, and it’s a list of product reviews. You can check the list of all the columns and their meaning on Amazon.

There are two significant elements you can extract from the data available:

  1. Products
  2. Reviews

A Product has:

  • ID
  • Title
  • Parent
  • Category

The Review has a few more fields:

  • ID
  • Customer ID
  • Stars
  • Headline
  • Body
  • Date

You can ignore a few of the review fields to make things a bit simpler.

So, a straightforward implementation of these two classes could be written in a separate file classes.py:

import datetime
from dataclasses import dataclass

@dataclass
class Product:
    id: str
    parent: str
    title: str
    category: str

@dataclass
class Review:
    id: str
    customer_id: str
    stars: int
    headline: str
    body: str
    date: datetime.datetime

After defining your data classes, you need to convert the data from the spreadsheet into these new structures.

Before doing the conversion, it’s worth looking at our header again and creating a mapping between columns and the fields you need:

>>>

>>> for value in sheet.iter_rows(min_row=1,
...                              max_row=1,
...                              values_only=True):
...     print(value)
('marketplace', 'customer_id', 'review_id', 'product_id', ...)

>>> # Or an alternative
>>> for cell in sheet[1]:
...     print(cell.value)
marketplace
customer_id
review_id
product_id
product_parent
...

Let’s create a file mapping.py where you have a list of all the field names and their column location (zero-indexed) on the spreadsheet:

# Product fields
PRODUCT_ID = 3
PRODUCT_PARENT = 4
PRODUCT_TITLE = 5
PRODUCT_CATEGORY = 6

# Review fields
REVIEW_ID = 2
REVIEW_CUSTOMER = 1
REVIEW_STARS = 7
REVIEW_HEADLINE = 12
REVIEW_BODY = 13
REVIEW_DATE = 14

You don’t necessarily have to do the mapping above. It’s more for readability when parsing the row data, so you don’t end up with a lot of magic numbers lying around.

Finally, let’s look at the code needed to parse the spreadsheet data into a list of product and review objects:

from datetime import datetime
from openpyxl import load_workbook
from classes import Product, Review
from mapping import PRODUCT_ID, PRODUCT_PARENT, PRODUCT_TITLE, 
    PRODUCT_CATEGORY, REVIEW_DATE, REVIEW_ID, REVIEW_CUSTOMER, 
    REVIEW_STARS, REVIEW_HEADLINE, REVIEW_BODY

# Using the read_only method since you're not gonna be editing the spreadsheet
workbook = load_workbook(filename="sample.xlsx", read_only=True)
sheet = workbook.active

products = []
reviews = []

# Using the values_only because you just want to return the cell value
for row in sheet.iter_rows(min_row=2, values_only=True):
    product = Product(id=row[PRODUCT_ID],
                      parent=row[PRODUCT_PARENT],
                      title=row[PRODUCT_TITLE],
                      category=row[PRODUCT_CATEGORY])
    products.append(product)

    # You need to parse the date from the spreadsheet into a datetime format
    spread_date = row[REVIEW_DATE]
    parsed_date = datetime.strptime(spread_date, "%Y-%m-%d")

    review = Review(id=row[REVIEW_ID],
                    customer_id=row[REVIEW_CUSTOMER],
                    stars=row[REVIEW_STARS],
                    headline=row[REVIEW_HEADLINE],
                    body=row[REVIEW_BODY],
                    date=parsed_date)
    reviews.append(review)

print(products[0])
print(reviews[0])

After you run the code above, you should get some output like this:

Product(id='B00FALQ1ZC', parent=937001370, ...)
Review(id='R3O9SGZBVQBV76', customer_id=3653882, ...)

That’s it! Now you should have the data in a very simple and digestible class format, and you can start thinking of storing this in a Database or any other type of data storage you like.

Using this kind of OOP strategy to parse spreadsheets makes handling the data much simpler later on.

Appending New Data

Before you start creating very complex spreadsheets, have a quick look at an example of how to append data to an existing spreadsheet.

Go back to the first example spreadsheet you created (hello_world.xlsx) and try opening it and appending some data to it, like this:

from openpyxl import load_workbook

# Start by opening the spreadsheet and selecting the main sheet
workbook = load_workbook(filename="hello_world.xlsx")
sheet = workbook.active

# Write what you want into a specific cell
sheet["C1"] = "writing ;)"

# Save the spreadsheet
workbook.save(filename="hello_world_append.xlsx")

Et voilà, if you open the new hello_world_append.xlsx spreadsheet, you’ll see the following change:

Appending Data to a Spreadsheet

Notice the additional writing ;) on cell C1.

Writing Excel Spreadsheets With openpyxl

There are a lot of different things you can write to a spreadsheet, from simple text or number values to complex formulas, charts, or even images.

Let’s start creating some spreadsheets!

Creating a Simple Spreadsheet

Previously, you saw a very quick example of how to write “Hello world!” into a spreadsheet, so you can start with that:

 1from openpyxl import Workbook
 2
 3filename = "hello_world.xlsx"
 4
 5workbook = Workbook()
 6sheet = workbook.active
 7
 8sheet["A1"] = "hello"
 9sheet["B1"] = "world!"
10
11workbook.save(filename=filename)

The highlighted lines in the code above are the most important ones for writing. In the code, you can see that:

  • Line 5 shows you how to create a new empty workbook.
  • Lines 8 and 9 show you how to add data to specific cells.
  • Line 11 shows you how to save the spreadsheet when you’re done.

Even though these lines above can be straightforward, it’s still good to know them well for when things get a bit more complicated.

One thing you can do to help with coming code examples is add the following method to your Python file or console:

>>>

>>> def print_rows():
...     for row in sheet.iter_rows(values_only=True):
...         print(row)

It makes it easier to print all of your spreadsheet values by just calling print_rows().

Basic Spreadsheet Operations

Before you get into the more advanced topics, it’s good for you to know how to manage the most simple elements of a spreadsheet.

Adding and Updating Cell Values

You already learned how to add values to a spreadsheet like this:

>>>

>>> sheet["A1"] = "value"

There’s another way you can do this, by first selecting a cell and then changing its value:

>>>

>>> cell = sheet["A1"]
>>> cell
<Cell 'Sheet'.A1>

>>> cell.value
'hello'

>>> cell.value = "hey"
>>> cell.value
'hey'

The new value is only stored into the spreadsheet once you call workbook.save().

The openpyxl creates a cell when adding a value, if that cell didn’t exist before:

>>>

>>> # Before, our spreadsheet has only 1 row
>>> print_rows()
('hello', 'world!')

>>> # Try adding a value to row 10
>>> sheet["B10"] = "test"
>>> print_rows()
('hello', 'world!')
(None, None)
(None, None)
(None, None)
(None, None)
(None, None)
(None, None)
(None, None)
(None, None)
(None, 'test')

As you can see, when trying to add a value to cell B10, you end up with a tuple with 10 rows, just so you can have that test value.

Managing Rows and Columns

One of the most common things you have to do when manipulating spreadsheets is adding or removing rows and columns. The openpyxl package allows you to do that in a very straightforward way by using the methods:

  • .insert_rows()
  • .delete_rows()
  • .insert_cols()
  • .delete_cols()

Every single one of those methods can receive two arguments:

  1. idx
  2. amount

Using our basic hello_world.xlsx example again, let’s see how these methods work:

>>>

>>> print_rows()
('hello', 'world!')

>>> # Insert a column before the existing column 1 ("A")
>>> sheet.insert_cols(idx=1)
>>> print_rows()
(None, 'hello', 'world!')

>>> # Insert 5 columns between column 2 ("B") and 3 ("C")
>>> sheet.insert_cols(idx=3, amount=5)
>>> print_rows()
(None, 'hello', None, None, None, None, None, 'world!')

>>> # Delete the created columns
>>> sheet.delete_cols(idx=3, amount=5)
>>> sheet.delete_cols(idx=1)
>>> print_rows()
('hello', 'world!')

>>> # Insert a new row in the beginning
>>> sheet.insert_rows(idx=1)
>>> print_rows()
(None, None)
('hello', 'world!')

>>> # Insert 3 new rows in the beginning
>>> sheet.insert_rows(idx=1, amount=3)
>>> print_rows()
(None, None)
(None, None)
(None, None)
(None, None)
('hello', 'world!')

>>> # Delete the first 4 rows
>>> sheet.delete_rows(idx=1, amount=4)
>>> print_rows()
('hello', 'world!')

The only thing you need to remember is that when inserting new data (rows or columns), the insertion happens before the idx parameter.

So, if you do insert_rows(1), it inserts a new row before the existing first row.

It’s the same for columns: when you call insert_cols(2), it inserts a new column right before the already existing second column (B).

However, when deleting rows or columns, .delete_... deletes data starting from the index passed as an argument.

For example, when doing delete_rows(2) it deletes row 2, and when doing delete_cols(3) it deletes the third column (C).

Managing Sheets

Sheet management is also one of those things you might need to know, even though it might be something that you don’t use that often.

If you look back at the code examples from this tutorial, you’ll notice the following recurring piece of code:

This is the way to select the default sheet from a spreadsheet. However, if you’re opening a spreadsheet with multiple sheets, then you can always select a specific one like this:

>>>

>>> # Let's say you have two sheets: "Products" and "Company Sales"
>>> workbook.sheetnames
['Products', 'Company Sales']

>>> # You can select a sheet using its title
>>> products_sheet = workbook["Products"]
>>> sales_sheet = workbook["Company Sales"]

You can also change a sheet title very easily:

>>>

>>> workbook.sheetnames
['Products', 'Company Sales']

>>> products_sheet = workbook["Products"]
>>> products_sheet.title = "New Products"

>>> workbook.sheetnames
['New Products', 'Company Sales']

If you want to create or delete sheets, then you can also do that with .create_sheet() and .remove():

>>>

>>> workbook.sheetnames
['Products', 'Company Sales']

>>> operations_sheet = workbook.create_sheet("Operations")
>>> workbook.sheetnames
['Products', 'Company Sales', 'Operations']

>>> # You can also define the position to create the sheet at
>>> hr_sheet = workbook.create_sheet("HR", 0)
>>> workbook.sheetnames
['HR', 'Products', 'Company Sales', 'Operations']

>>> # To remove them, just pass the sheet as an argument to the .remove()
>>> workbook.remove(operations_sheet)
>>> workbook.sheetnames
['HR', 'Products', 'Company Sales']

>>> workbook.remove(hr_sheet)
>>> workbook.sheetnames
['Products', 'Company Sales']

One other thing you can do is make duplicates of a sheet using copy_worksheet():

>>>

>>> workbook.sheetnames
['Products', 'Company Sales']

>>> products_sheet = workbook["Products"]
>>> workbook.copy_worksheet(products_sheet)
<Worksheet "Products Copy">

>>> workbook.sheetnames
['Products', 'Company Sales', 'Products Copy']

If you open your spreadsheet after saving the above code, you’ll notice that the sheet Products Copy is a duplicate of the sheet Products.

Freezing Rows and Columns

Something that you might want to do when working with big spreadsheets is to freeze a few rows or columns, so they remain visible when you scroll right or down.

Freezing data allows you to keep an eye on important rows or columns, regardless of where you scroll in the spreadsheet.

Again, openpyxl also has a way to accomplish this by using the worksheet freeze_panes attribute. For this example, go back to our sample.xlsx spreadsheet and try doing the following:

>>>

>>> workbook = load_workbook(filename="sample.xlsx")
>>> sheet = workbook.active
>>> sheet.freeze_panes = "C2"
>>> workbook.save("sample_frozen.xlsx")

If you open the sample_frozen.xlsx spreadsheet in your favorite spreadsheet editor, you’ll notice that row 1 and columns A and B are frozen and are always visible no matter where you navigate within the spreadsheet.

This feature is handy, for example, to keep headers within sight, so you always know what each column represents.

Here’s how it looks in the editor:

Example Spreadsheet With Frozen Rows and Columns

Notice how you’re at the end of the spreadsheet, and yet, you can see both row 1 and columns A and B.

Adding Filters

You can use openpyxl to add filters and sorts to your spreadsheet. However, when you open the spreadsheet, the data won’t be rearranged according to these sorts and filters.

At first, this might seem like a pretty useless feature, but when you’re programmatically creating a spreadsheet that is going to be sent and used by somebody else, it’s still nice to at least create the filters and allow people to use it afterward.

The code below is an example of how you would add some filters to our existing sample.xlsx spreadsheet:

>>>

>>> # Check the used spreadsheet space using the attribute "dimensions"
>>> sheet.dimensions
'A1:O100'

>>> sheet.auto_filter.ref = "A1:O100"
>>> workbook.save(filename="sample_with_filters.xlsx")

You should now see the filters created when opening the spreadsheet in your editor:

Example Spreadsheet With Filters

You don’t have to use sheet.dimensions if you know precisely which part of the spreadsheet you want to apply filters to.

Adding Formulas

Formulas (or formulae) are one of the most powerful features of spreadsheets.

They gives you the power to apply specific mathematical equations to a range of cells. Using formulas with openpyxl is as simple as editing the value of a cell.

You can see the list of formulas supported by openpyxl:

>>>

>>> from openpyxl.utils import FORMULAE
>>> FORMULAE
frozenset({'ABS',
           'ACCRINT',
           'ACCRINTM',
           'ACOS',
           'ACOSH',
           'AMORDEGRC',
           'AMORLINC',
           'AND',
           ...
           'YEARFRAC',
           'YIELD',
           'YIELDDISC',
           'YIELDMAT',
           'ZTEST'})

Let’s add some formulas to our sample.xlsx spreadsheet.

Starting with something easy, let’s check the average star rating for the 99 reviews within the spreadsheet:

>>>

>>> # Star rating is column "H"
>>> sheet["P2"] = "=AVERAGE(H2:H100)"
>>> workbook.save(filename="sample_formulas.xlsx")

If you open the spreadsheet now and go to cell P2, you should see that its value is: 4.18181818181818. Have a look in the editor:

Example Spreadsheet With Average Formula

You can use the same methodology to add any formulas to your spreadsheet. For example, let’s count the number of reviews that had helpful votes:

>>>

>>> # The helpful votes are counted on column "I"
>>> sheet["P3"] = '=COUNTIF(I2:I100, ">0")'
>>> workbook.save(filename="sample_formulas.xlsx")

You should get the number 21 on your P3 spreadsheet cell like so:

Example Spreadsheet With Average and CountIf Formula

You’ll have to make sure that the strings within a formula are always in double quotes, so you either have to use single quotes around the formula like in the example above or you’ll have to escape the double quotes inside the formula: "=COUNTIF(I2:I100, ">0")".

There are a ton of other formulas you can add to your spreadsheet using the same procedure you tried above. Give it a go yourself!

Adding Styles

Even though styling a spreadsheet might not be something you would do every day, it’s still good to know how to do it.

Using openpyxl, you can apply multiple styling options to your spreadsheet, including fonts, borders, colors, and so on. Have a look at the openpyxl documentation to learn more.

You can also choose to either apply a style directly to a cell or create a template and reuse it to apply styles to multiple cells.

Let’s start by having a look at simple cell styling, using our sample.xlsx again as the base spreadsheet:

>>>

>>> # Import necessary style classes
>>> from openpyxl.styles import Font, Color, Alignment, Border, Side

>>> # Create a few styles
>>> bold_font = Font(bold=True)
>>> big_red_text = Font(color="00FF0000", size=20)
>>> center_aligned_text = Alignment(horizontal="center")
>>> double_border_side = Side(border_style="double")
>>> square_border = Border(top=double_border_side,
...                        right=double_border_side,
...                        bottom=double_border_side,
...                        left=double_border_side)

>>> # Style some cells!
>>> sheet["A2"].font = bold_font
>>> sheet["A3"].font = big_red_text
>>> sheet["A4"].alignment = center_aligned_text
>>> sheet["A5"].border = square_border
>>> workbook.save(filename="sample_styles.xlsx")

If you open your spreadsheet now, you should see quite a few different styles on the first 5 cells of column A:

Example Spreadsheet With Simple Cell Styles

There you go. You got:

  • A2 with the text in bold
  • A3 with the text in red and bigger font size
  • A4 with the text centered
  • A5 with a square border around the text

You can also combine styles by simply adding them to the cell at the same time:

>>>

>>> # Reusing the same styles from the example above
>>> sheet["A6"].alignment = center_aligned_text
>>> sheet["A6"].font = big_red_text
>>> sheet["A6"].border = square_border
>>> workbook.save(filename="sample_styles.xlsx")

Have a look at cell A6 here:

Example Spreadsheet With Coupled Cell Styles

When you want to apply multiple styles to one or several cells, you can use a NamedStyle class instead, which is like a style template that you can use over and over again. Have a look at the example below:

>>>

>>> from openpyxl.styles import NamedStyle

>>> # Let's create a style template for the header row
>>> header = NamedStyle(name="header")
>>> header.font = Font(bold=True)
>>> header.border = Border(bottom=Side(border_style="thin"))
>>> header.alignment = Alignment(horizontal="center", vertical="center")

>>> # Now let's apply this to all first row (header) cells
>>> header_row = sheet[1]
>>> for cell in header_row:
...     cell.style = header

>>> workbook.save(filename="sample_styles.xlsx")

If you open the spreadsheet now, you should see that its first row is bold, the text is aligned to the center, and there’s a small bottom border! Have a look below:

Example Spreadsheet With Named Styles

As you saw above, there are many options when it comes to styling, and it depends on the use case, so feel free to check openpyxl documentation and see what other things you can do.

Conditional Formatting

This feature is one of my personal favorites when it comes to adding styles to a spreadsheet.

It’s a much more powerful approach to styling because it dynamically applies styles according to how the data in the spreadsheet changes.

In a nutshell, conditional formatting allows you to specify a list of styles to apply to a cell (or cell range) according to specific conditions.

For example, a widespread use case is to have a balance sheet where all the negative totals are in red, and the positive ones are in green. This formatting makes it much more efficient to spot good vs bad periods.

Without further ado, let’s pick our favorite spreadsheet—sample.xlsx—and add some conditional formatting.

You can start by adding a simple one that adds a red background to all reviews with less than 3 stars:

>>>

>>> from openpyxl.styles import PatternFill
>>> from openpyxl.styles.differential import DifferentialStyle
>>> from openpyxl.formatting.rule import Rule

>>> red_background = PatternFill(fgColor="00FF0000")
>>> diff_style = DifferentialStyle(fill=red_background)
>>> rule = Rule(type="expression", dxf=diff_style)
>>> rule.formula = ["$H1<3"]
>>> sheet.conditional_formatting.add("A1:O100", rule)
>>> workbook.save("sample_conditional_formatting.xlsx")

Now you’ll see all the reviews with a star rating below 3 marked with a red background:

Example Spreadsheet With Simple Conditional Formatting

Code-wise, the only things that are new here are the objects DifferentialStyle and Rule:

  • DifferentialStyle is quite similar to NamedStyle, which you already saw above, and it’s used to aggregate multiple styles such as fonts, borders, alignment, and so forth.
  • Rule is responsible for selecting the cells and applying the styles if the cells match the rule’s logic.

Using a Rule object, you can create numerous conditional formatting scenarios.

However, for simplicity sake, the openpyxl package offers 3 built-in formats that make it easier to create a few common conditional formatting patterns. These built-ins are:

  • ColorScale
  • IconSet
  • DataBar

The ColorScale gives you the ability to create color gradients:

>>>

>>> from openpyxl.formatting.rule import ColorScaleRule
>>> color_scale_rule = ColorScaleRule(start_type="min",
...                                   start_color="00FF0000",  # Red
...                                   end_type="max",
...                                   end_color="0000FF00")  # Green

>>> # Again, let's add this gradient to the star ratings, column "H"
>>> sheet.conditional_formatting.add("H2:H100", color_scale_rule)
>>> workbook.save(filename="sample_conditional_formatting_color_scale.xlsx")

Now you should see a color gradient on column H, from red to green, according to the star rating:

Example Spreadsheet With Color Scale Conditional Formatting

You can also add a third color and make two gradients instead:

>>>

>>> from openpyxl.formatting.rule import ColorScaleRule
>>> color_scale_rule = ColorScaleRule(start_type="num",
...                                   start_value=1,
...                                   start_color="00FF0000",  # Red
...                                   mid_type="num",
...                                   mid_value=3,
...                                   mid_color="00FFFF00",  # Yellow
...                                   end_type="num",
...                                   end_value=5,
...                                   end_color="0000FF00")  # Green

>>> # Again, let's add this gradient to the star ratings, column "H"
>>> sheet.conditional_formatting.add("H2:H100", color_scale_rule)
>>> workbook.save(filename="sample_conditional_formatting_color_scale_3.xlsx")

This time, you’ll notice that star ratings between 1 and 3 have a gradient from red to yellow, and star ratings between 3 and 5 have a gradient from yellow to green:

Example Spreadsheet With 2 Color Scales Conditional Formatting

The IconSet allows you to add an icon to the cell according to its value:

>>>

>>> from openpyxl.formatting.rule import IconSetRule

>>> icon_set_rule = IconSetRule("5Arrows", "num", [1, 2, 3, 4, 5])
>>> sheet.conditional_formatting.add("H2:H100", icon_set_rule)
>>> workbook.save("sample_conditional_formatting_icon_set.xlsx")

You’ll see a colored arrow next to the star rating. This arrow is red and points down when the value of the cell is 1 and, as the rating gets better, the arrow starts pointing up and becomes green:

Example Spreadsheet With Icon Set Conditional Formatting

The openpyxl package has a full list of other icons you can use, besides the arrow.

Finally, the DataBar allows you to create progress bars:

>>>

>>> from openpyxl.formatting.rule import DataBarRule

>>> data_bar_rule = DataBarRule(start_type="num",
...                             start_value=1,
...                             end_type="num",
...                             end_value="5",
...                             color="0000FF00")  # Green
>>> sheet.conditional_formatting.add("H2:H100", data_bar_rule)
>>> workbook.save("sample_conditional_formatting_data_bar.xlsx")

You’ll now see a green progress bar that gets fuller the closer the star rating is to the number 5:

Example Spreadsheet With Data Bar Conditional Formatting

As you can see, there are a lot of cool things you can do with conditional formatting.

Here, you saw only a few examples of what you can achieve with it, but check the openpyxl documentation to see a bunch of other options.

Adding Images

Even though images are not something that you’ll often see in a spreadsheet, it’s quite cool to be able to add them. Maybe you can use it for branding purposes or to make spreadsheets more personal.

To be able to load images to a spreadsheet using openpyxl, you’ll have to install Pillow:

Apart from that, you’ll also need an image. For this example, you can grab the Real Python logo below and convert it from .webp to .png using an online converter such as cloudconvert.com, save the final file as logo.png, and copy it to the root folder where you’re running your examples:

Real Python Logo

Afterward, this is the code you need to import that image into the hello_word.xlsx spreadsheet:

from openpyxl import load_workbook
from openpyxl.drawing.image import Image

# Let's use the hello_world spreadsheet since it has less data
workbook = load_workbook(filename="hello_world.xlsx")
sheet = workbook.active

logo = Image("logo.png")

# A bit of resizing to not fill the whole spreadsheet with the logo
logo.height = 150
logo.width = 150

sheet.add_image(logo, "A3")
workbook.save(filename="hello_world_logo.xlsx")

You have an image on your spreadsheet! Here it is:

Example Spreadsheet With Image

The image’s left top corner is on the cell you chose, in this case, A3.

Adding Pretty Charts

Another powerful thing you can do with spreadsheets is create an incredible variety of charts.

Charts are a great way to visualize and understand loads of data quickly. There are a lot of different chart types: bar chart, pie chart, line chart, and so on. openpyxl has support for a lot of them.

Here, you’ll see only a couple of examples of charts because the theory behind it is the same for every single chart type:

For any chart you want to build, you’ll need to define the chart type: BarChart, LineChart, and so forth, plus the data to be used for the chart, which is called Reference.

Before you can build your chart, you need to define what data you want to see represented in it. Sometimes, you can use the dataset as is, but other times you need to massage the data a bit to get additional information.

Let’s start by building a new workbook with some sample data:

 1from openpyxl import Workbook
 2from openpyxl.chart import BarChart, Reference
 3
 4workbook = Workbook()
 5sheet = workbook.active
 6
 7# Let's create some sample sales data
 8rows = [
 9    ["Product", "Online", "Store"],
10    [1, 30, 45],
11    [2, 40, 30],
12    [3, 40, 25],
13    [4, 50, 30],
14    [5, 30, 25],
15    [6, 25, 35],
16    [7, 20, 40],
17]
18
19for row in rows:
20    sheet.append(row)

Now you’re going to start by creating a bar chart that displays the total number of sales per product:

22chart = BarChart()
23data = Reference(worksheet=sheet,
24                 min_row=1,
25                 max_row=8,
26                 min_col=2,
27                 max_col=3)
28
29chart.add_data(data, titles_from_data=True)
30sheet.add_chart(chart, "E2")
31
32workbook.save("chart.xlsx")

There you have it. Below, you can see a very straightforward bar chart showing the difference between online product sales online and in-store product sales:

Example Spreadsheet With Bar Chart

Like with images, the top left corner of the chart is on the cell you added the chart to. In your case, it was on cell E2.

Try creating a line chart instead, changing the data a bit:

 1import random
 2from openpyxl import Workbook
 3from openpyxl.chart import LineChart, Reference
 4
 5workbook = Workbook()
 6sheet = workbook.active
 7
 8# Let's create some sample sales data
 9rows = [
10    ["", "January", "February", "March", "April",
11    "May", "June", "July", "August", "September",
12     "October", "November", "December"],
13    [1, ],
14    [2, ],
15    [3, ],
16]
17
18for row in rows:
19    sheet.append(row)
20
21for row in sheet.iter_rows(min_row=2,
22                           max_row=4,
23                           min_col=2,
24                           max_col=13):
25    for cell in row:
26        cell.value = random.randrange(5, 100)

With the above code, you’ll be able to generate some random data regarding the sales of 3 different products across a whole year.

Once that’s done, you can very easily create a line chart with the following code:

28chart = LineChart()
29data = Reference(worksheet=sheet,
30                 min_row=2,
31                 max_row=4,
32                 min_col=1,
33                 max_col=13)
34
35chart.add_data(data, from_rows=True, titles_from_data=True)
36sheet.add_chart(chart, "C6")
37
38workbook.save("line_chart.xlsx")

Here’s the outcome of the above piece of code:

Example Spreadsheet With Line Chart

One thing to keep in mind here is the fact that you’re using from_rows=True when adding the data. This argument makes the chart plot row by row instead of column by column.

In your sample data, you see that each product has a row with 12 values (1 column per month). That’s why you use from_rows. If you don’t pass that argument, by default, the chart tries to plot by column, and you’ll get a month-by-month comparison of sales.

Another difference that has to do with the above argument change is the fact that our Reference now starts from the first column, min_col=1, instead of the second one. This change is needed because the chart now expects the first column to have the titles.

There are a couple of other things you can also change regarding the style of the chart. For example, you can add specific categories to the chart:

cats = Reference(worksheet=sheet,
                 min_row=1,
                 max_row=1,
                 min_col=2,
                 max_col=13)
chart.set_categories(cats)

Add this piece of code before saving the workbook, and you should see the month names appearing instead of numbers:

Example Spreadsheet With Line Chart and Categories

Code-wise, this is a minimal change. But in terms of the readability of the spreadsheet, this makes it much easier for someone to open the spreadsheet and understand the chart straight away.

Another thing you can do to improve the chart readability is to add an axis. You can do it using the attributes x_axis and y_axis:

chart.x_axis.title = "Months"
chart.y_axis.title = "Sales (per unit)"

This will generate a spreadsheet like the below one:

Example Spreadsheet With Line Chart, Categories and Axis Titles

As you can see, small changes like the above make reading your chart a much easier and quicker task.

There is also a way to style your chart by using Excel’s default ChartStyle property. In this case, you have to choose a number between 1 and 48. Depending on your choice, the colors of your chart change as well:

# You can play with this by choosing any number between 1 and 48
chart.style = 24

With the style selected above, all lines have some shade of orange:

Example Spreadsheet With Line Chart, Categories, Axis Titles and Style

There is no clear documentation on what each style number looks like, but this spreadsheet has a few examples of the styles available.

Here’s the full code used to generate the line chart with categories, axis titles, and style:

import random
from openpyxl import Workbook
from openpyxl.chart import LineChart, Reference

workbook = Workbook()
sheet = workbook.active

# Let's create some sample sales data
rows = [
    ["", "January", "February", "March", "April",
    "May", "June", "July", "August", "September",
     "October", "November", "December"],
    [1, ],
    [2, ],
    [3, ],
]

for row in rows:
    sheet.append(row)

for row in sheet.iter_rows(min_row=2,
                           max_row=4,
                           min_col=2,
                           max_col=13):
    for cell in row:
        cell.value = random.randrange(5, 100)

# Create a LineChart and add the main data
chart = LineChart()
data = Reference(worksheet=sheet,
                           min_row=2,
                           max_row=4,
                           min_col=1,
                           max_col=13)
chart.add_data(data, titles_from_data=True, from_rows=True)

# Add categories to the chart
cats = Reference(worksheet=sheet,
                 min_row=1,
                 max_row=1,
                 min_col=2,
                 max_col=13)
chart.set_categories(cats)

# Rename the X and Y Axis
chart.x_axis.title = "Months"
chart.y_axis.title = "Sales (per unit)"

# Apply a specific Style
chart.style = 24

# Save!
sheet.add_chart(chart, "C6")
workbook.save("line_chart.xlsx")

There are a lot more chart types and customization you can apply, so be sure to check out the package documentation on this if you need some specific formatting.

Convert Python Classes to Excel Spreadsheet

You already saw how to convert an Excel spreadsheet’s data into Python classes, but now let’s do the opposite.

Let’s imagine you have a database and are using some Object-Relational Mapping (ORM) to map DB objects into Python classes. Now, you want to export those same objects into a spreadsheet.

Let’s assume the following data classes to represent the data coming from your database regarding product sales:

from dataclasses import dataclass
from typing import List

@dataclass
class Sale:
    quantity: int

@dataclass
class Product:
    id: str
    name: str
    sales: List[Sale]

Now, let’s generate some random data, assuming the above classes are stored in a db_classes.py file:

 1import random
 2
 3# Ignore these for now. You'll use them in a sec ;)
 4from openpyxl import Workbook
 5from openpyxl.chart import LineChart, Reference
 6
 7from db_classes import Product, Sale
 8
 9products = []
10
11# Let's create 5 products
12for idx in range(1, 6):
13    sales = []
14
15    # Create 5 months of sales
16    for _ in range(5):
17        sale = Sale(quantity=random.randrange(5, 100))
18        sales.append(sale)
19
20    product = Product(id=str(idx),
21                      name="Product %s" % idx,
22                      sales=sales)
23    products.append(product)

By running this piece of code, you should get 5 products with 5 months of sales with a random quantity of sales for each month.

Now, to convert this into a spreadsheet, you need to iterate over the data and append it to the spreadsheet:

25workbook = Workbook()
26sheet = workbook.active
27
28# Append column names first
29sheet.append(["Product ID", "Product Name", "Month 1",
30              "Month 2", "Month 3", "Month 4", "Month 5"])
31
32# Append the data
33for product in products:
34    data = [product.id, product.name]
35    for sale in product.sales:
36        data.append(sale.quantity)
37    sheet.append(data)

That’s it. That should allow you to create a spreadsheet with some data coming from your database.

However, why not use some of that cool knowledge you gained recently to add a chart as well to display that data more visually?

All right, then you could probably do something like this:

38chart = LineChart()
39data = Reference(worksheet=sheet,
40                 min_row=2,
41                 max_row=6,
42                 min_col=2,
43                 max_col=7)
44
45chart.add_data(data, titles_from_data=True, from_rows=True)
46sheet.add_chart(chart, "B8")
47
48cats = Reference(worksheet=sheet,
49                 min_row=1,
50                 max_row=1,
51                 min_col=3,
52                 max_col=7)
53chart.set_categories(cats)
54
55chart.x_axis.title = "Months"
56chart.y_axis.title = "Sales (per unit)"
57
58workbook.save(filename="oop_sample.xlsx")

Now we’re talking! Here’s a spreadsheet generated from database objects and with a chart and everything:

Example Spreadsheet With Conversion from Python Data Classes

That’s a great way for you to wrap up your new knowledge of charts!

Bonus: Working With Pandas

Even though you can use Pandas to handle Excel files, there are few things that you either can’t accomplish with Pandas or that you’d be better off just using openpyxl directly.

For example, some of the advantages of using openpyxl are the ability to easily customize your spreadsheet with styles, conditional formatting, and such.

But guess what, you don’t have to worry about picking. In fact, openpyxl has support for both converting data from a Pandas DataFrame into a workbook or the opposite, converting an openpyxl workbook into a Pandas DataFrame.

First things first, remember to install the pandas package:

Then, let’s create a sample DataFrame:

 1import pandas as pd
 2
 3data = {
 4    "Product Name": ["Product 1", "Product 2"],
 5    "Sales Month 1": [10, 20],
 6    "Sales Month 2": [5, 35],
 7}
 8df = pd.DataFrame(data)

Now that you have some data, you can use .dataframe_to_rows() to convert it from a DataFrame into a worksheet:

10from openpyxl import Workbook
11from openpyxl.utils.dataframe import dataframe_to_rows
12
13workbook = Workbook()
14sheet = workbook.active
15
16for row in dataframe_to_rows(df, index=False, header=True):
17    sheet.append(row)
18
19workbook.save("pandas.xlsx")

You should see a spreadsheet that looks like this:

Example Spreadsheet With Data from Pandas Data Frame

If you want to add the DataFrame’s index, you can change index=True, and it adds each row’s index into your spreadsheet.

On the other hand, if you want to convert a spreadsheet into a DataFrame, you can also do it in a very straightforward way like so:

import pandas as pd
from openpyxl import load_workbook

workbook = load_workbook(filename="sample.xlsx")
sheet = workbook.active

values = sheet.values
df = pd.DataFrame(values)

Alternatively, if you want to add the correct headers and use the review ID as the index, for example, then you can also do it like this instead:

import pandas as pd
from openpyxl import load_workbook
from mapping import REVIEW_ID

workbook = load_workbook(filename="sample.xlsx")
sheet = workbook.active

data = sheet.values

# Set the first row as the columns for the DataFrame
cols = next(data)
data = list(data)

# Set the field "review_id" as the indexes for each row
idx = [row[REVIEW_ID] for row in data]

df = pd.DataFrame(data, index=idx, columns=cols)

Using indexes and columns allows you to access data from your DataFrame easily:

>>>

>>> df.columns
Index(['marketplace', 'customer_id', 'review_id', 'product_id',
       'product_parent', 'product_title', 'product_category', 'star_rating',
       'helpful_votes', 'total_votes', 'vine', 'verified_purchase',
       'review_headline', 'review_body', 'review_date'],
      dtype='object')

>>> # Get first 10 reviews' star rating
>>> df["star_rating"][:10]
R3O9SGZBVQBV76    5
RKH8BNC3L5DLF     5
R2HLE8WKZSU3NL    2
R31U3UH5AZ42LL    5
R2SV659OUJ945Y    4
RA51CP8TR5A2L     5
RB2Q7DLDN6TH6     5
R2RHFJV0UYBK3Y    1
R2Z6JOQ94LFHEP    5
RX27XIIWY5JPB     4
Name: star_rating, dtype: int64

>>> # Grab review with id "R2EQL1V1L6E0C9", using the index
>>> df.loc["R2EQL1V1L6E0C9"]
marketplace               US
customer_id         15305006
review_id     R2EQL1V1L6E0C9
product_id        B004LURNO6
product_parent     892860326
review_headline   Five Stars
review_body          Love it
review_date       2015-08-31
Name: R2EQL1V1L6E0C9, dtype: object

There you go, whether you want to use openpyxl to prettify your Pandas dataset or use Pandas to do some hardcore algebra, you now know how to switch between both packages.

Conclusion

Phew, after that long read, you now know how to work with spreadsheets in Python! You can rely on openpyxl, your trustworthy companion, to:

  • Extract valuable information from spreadsheets in a Pythonic manner
  • Create your own spreadsheets, no matter the complexity level
  • Add cool features such as conditional formatting or charts to your spreadsheets

There are a few other things you can do with openpyxl that might not have been covered in this tutorial, but you can always check the package’s official documentation website to learn more about it. You can even venture into checking its source code and improving the package further.

Feel free to leave any comments below if you have any questions, or if there’s any section you’d love to hear more about.

Watch Now This tutorial has a related video course created by the Real Python team. Watch it together with the written tutorial to deepen your understanding: Editing Excel Spreadsheets in Python With openpyxl

Learn how to use this handy library to work with Excel spreadsheets outside of Excel.

People sitting at a table with Computer Screen showing Excel Graphs

Excel spreadsheets can be powerful, but some tasks may call for more programming power. Enter Python and the Openpyxl module.

Openpyxl provides functions that allow you to work with an Excel file from Python. You can use it to process data, create new spreadsheets, and even manipulate formulae.

The library is handy if you need to automate the same repetitive calculations over many Excel files. This may be the case if you need to deal with big data or perform data analysis.

How to Install the Openpyxl Module

First, install Openpyxl onto your computer with these steps:

  1. Open a command prompt and run the following:
     pip install openpyxl 
  2. If the above does not work, you can download the module from Openpyxl’s Download Files page:
    Browser open to page where you can download Openpyxl
    1. Download the openpyxl-version.tar.gz file.
    2. Extract the file’s contents.
    3. Open a command prompt. Navigate to the folder of the extracted files and run the following command:
       py setup.py install 

Create Your Excel Files and Test Data

Create many Excel files and add some test data to them. If you are new to Excel, there are lots of tools that can help you learn it.

  1. Create several Excel files in the same folder. In this scenario, there are five Excel files. Each file stores population data for three different countries.
    Windows File Explorer open showing many Excel files
  2. In each Excel file, add some test data. For example:
    Excel File opened with table of population data

This example includes data relating to the population of many countries.

How to Create the Python Script

Create the Python Script as follows:

  1. Create a new file called dataAnalysisScript.py. Open it using any good text editor, like Visual Studio Code or Atom.
  2. Add the following three imports at the top of the file. «os» and «sys» relate to accessing files on your computer or closing the program. «openpyxl» is the module downloaded in the previous step that allows you to read and write Excel files.
     import openpyxl
    import os
    import sys
  3. Below the imports, add the basic structure of the Python script below. Keep in mind that the code structure in Python depends on correct indentation.
     # Main, start of the program
    if __name__ == "__main__":
        while True:
            # Write code here
            # When the code finishes, close the program.
            sys.exit()
  4. Inside the while loop, add a prompt for the user to enter the path to the folder that contains the Excel files.
     if __name__ == "__main__":
      while True:
        # Asks the user to enter the filepath of the excel file.
        filePath = input('Please enter the path of the folder where the excel files are stored: ')
        # Goes inside that folder.
        os.chdir(filePath)
        # Gets the list of excel files inside the folder.
        excelFiles = os.listdir('.')

How to Read and Write Data From the Excel Files

Use a for loop to open, read, manipulate, and close each of the Excel files.

  1. Add a for loop for each Excel file. Inside the loop, open each file.
     # For each Excel file
    for i in range(0, len(excelFiles)):
        # This is using the openpyxl module to open the Excel file.
        wb = openpyxl.load_workbook(excelFiles[i])
        sheet = wb.active
  2. The following code reads a specific value from a particular cell:
     cellValue = sheet[f'B3'].value
  3. The following code writes data to the cell «A10»:
     sheet<strong>[</strong>f'A10'<strong>].</strong>value <strong>=</strong> 56 

    You can also write to the cell by specifying the row and column number. The following code adds the number «2» into cell «F1».

     sheet.cell(row=1, column=6).value = 2

How to Perform Built-In Excel Functions Using the Python Script

For each Excel file, calculate the sum, average, and standard deviation for each «country» column. The following code calculates the sum of all numbers for each country:

 sheet[f'B11'].value = '=SUM(B4:B9)' 
sheet[f'C11'].value = '=SUM(C4:C9)'
sheet[f'D11'].value = '=SUM(D4:D9)'
  • ‘=SUM(B4:B9)’ is the Excel calculation that will add all numbers in the B column between cells B4 and B9.
  • sheet[f’B11′].value is the value in cell B11. The program will store the final result in this cell.

You can also calculate the average and standard deviation Excel functions in the same way shown above.

 sheet[f'B12'].value = '=AVERAGE(B4:B9)'
sheet[f'C12'].value = '=AVERAGE(C4:C9)'
sheet[f'D12'].value = '=AVERAGE(D4:D9)'
 sheet[f'B13'].value = '=STDEV(B4:B9)' 
sheet[f'C13'].value = '=STDEV(C4:C9)'
sheet[f'D13'].value = '=STDEV(D4:D9)'

Excel File opened with Sum, Average, and Standard Deviation Filled

How to Write to the File and Close the Workbook

The remaining code saves and closes each workbook, then closes the program.

  1. Inside the for loop, after performing the required Excel functions, save the changes made to the Excel file.
     wb.save(excelFiles[i])
    print(excelFiles[i] + ' completed.')
  2. Outside the for loop, close the Python Script.
     sys.exit() 

The code altogether:

 # Main, start of the program
if __name__ == "__main__":
  while True:
    filePath = input('Please enter the path of the folder where the excel files are stored: ')
    os.chdir(filePath)
    excelFiles = os.listdir('.')

        # For each excel file
    for i in range(0, len(excelFiles)):

            wb = openpyxl.load_workbook(excelFiles[i])
        sheet = wb.active

                # Perform all required Excel functions as shown above here

                # Save and close the workbook
        wb.save(excelFiles[i])
        print(excelFiles[i] + ' completed.')

        # When the code finishes, close the program.
    sys.exit()

How to Run the Python Script

  1. Open the command prompt. Navigate to where you stored your script. If you stored your script on the Desktop, the command would look something like this:
     cd C:UsersSharlDesktop 
  2. Enter the following to run the script:
     python dataAnalysisScript.py 
  3. The script will start by asking you to enter the folder that stores all your Excel files. As an example, if you stored this folder on the desktop, the file path would be:
     C:UsersSharlDesktopCountryData 
  4. Open one of the Excel files in the folder to view the changes made.

Make sure none of the Excel files are open when you run the script.

Automating More With Python

Now you have the basics of how to perform Excel functions inside a Python Script. You can now learn how to perform many more Excel functions, as well as many other ways to automate Excel files. This includes using a library like Pandas to import data, or even using Visual Basic to perform repetitive tasks in Excel.

I am basically trying to copy some specific columns from a CSV file and paste those
in an existing excel file[*.xlsx] using python. Say for example, you have a CSV file like this :

 col_1   col_2   col_3  col_4
  1        2       3     4
  5        6       7     8
  9       10      11    12 

So, i wanted to copy the both col_3 and col_4 and paste those in col_8 and col_9 in an existing excel file [which is a .XLSX format].
I have tried this in various way to solve, but could not find out the exact way.
i tried something like this :

with open( read_x_csv, 'rb') as f:
    reader = csv.reader(f)
    for row in reader: 
            list1 = row[13] 
            queue1.append(list1)
            list2 = row[14] 
            queue2.append(list2)
            list3 = row[15] 
            queue3.append(list3)
            list4 = row[16] 
            queue4.append(list4)

and then

 rb = open_workbook("Exact file path.....")
 wb = copy(rb)
 ws = wb.get_sheet(0) 

 row_no = 0

 for item in queue1:
    if(item != ""):
            ii = int(item)
            ws.write(row_no,12,ii) 
            row_no = row_no + 1
            #ws.write(item)
            print item
    else:

            ws.write(row_no,12,item) 
            row_no = row_no + 1

  wb.save("Output.xls") 

but problem with this solution is it does not allow me to save as *.XLSX format which is
strictly required for me.

I have tried to use Openpyxl as it can handle *.XLSX format, but could not find out a way to modify the existing excel file. can anyone please help on this?

Doubt :
1) Can we really read a whole column from a CSV file and store into an array/list
using python?
2) Can we modify the existing excel file which is in .XLSX format using
openpyxl or any other package?

Узнайте, как читать и импортировать файлы Excel в Python, как записывать данные в эти таблицы и какие библиотеки лучше всего подходят для этого.

Известный вам инструмент для организации, анализа и хранения ваших данных в таблицах — Excel — применяется и в data science. В какой-то момент вам придется иметь дело с этими таблицами, но работать именно с ними вы будете не всегда. Вот почему разработчики Python реализовали способы чтения, записи и управления не только этими файлами, но и многими другими типами файлов.

Из этого учебника узнаете, как можете работать с Excel и Python. Внутри найдете обзор библиотек, которые вы можете использовать для загрузки и записи этих таблиц в файлы с помощью Python. Вы узнаете, как работать с такими библиотеками, как pandas, openpyxl, xlrd, xlutils и pyexcel.

Данные как ваша отправная точка

Когда вы начинаете проект по data science, вам придется работать с данными, которые вы собрали по всему интернету, и с наборами данных, которые вы загрузили из других мест — Kaggle, Quandl и тд

Но чаще всего вы также найдете данные в Google или в репозиториях, которые используются другими пользователями. Эти данные могут быть в файле Excel или сохранены в файл с расширением .csv … Возможности могут иногда казаться бесконечными, но когда у вас есть данные, в первую очередь вы должны убедиться, что они качественные.

В случае с электронной таблицей вы можете не только проверить, могут ли эти данные ответить на вопрос исследования, который вы имеете в виду, но также и можете ли вы доверять данным, которые хранятся в электронной таблице.

Проверяем качество таблицы

  • Представляет ли электронная таблица статические данные?
  • Смешивает ли она данные, расчеты и отчетность?
  • Являются ли данные в вашей электронной таблице полными и последовательными?
  • Имеет ли ваша таблица систематизированную структуру рабочего листа?
  • Проверяли ли вы действительные формулы в электронной таблице?

Этот список вопросов поможет убедиться, что ваша таблица не грешит против лучших практик, принятых в отрасли. Конечно, этот список не исчерпывающий, но позволит провести базовую проверку таблицы.

Лучшие практики для данных электронных таблиц

Прежде чем приступить к чтению вашей электронной таблицы на Python, вы также должны подумать о том, чтобы настроить свой файл в соответствии с некоторыми основными принципами, такими как:

  • Первая строка таблицы обычно зарезервирована для заголовка, а первый столбец используется для идентификации единицы выборки;
  • Избегайте имен, значений или полей с пробелами. В противном случае каждое слово будет интерпретироваться как отдельная переменная, что приведет к ошибкам, связанным с количеством элементов на строку в вашем наборе данных. По возможности, используйте:
  • подчеркивания,
  • тире,
  • горбатый регистр, где первая буква каждого слова пишется с большой буквы
  • объединяющие слова
  • Короткие имена предпочтительнее длинных имен;
  • старайтесь не использовать имена, которые содержат символы ?, $,%, ^, &, *, (,), -, #,? ,,, <,>, /, |, , [,], {, и };
  • Удалите все комментарии, которые вы сделали в вашем файле, чтобы избежать добавления в ваш файл лишних столбцов или NA;
  • Убедитесь, что все пропущенные значения в вашем наборе данных обозначены как NA.

Затем, после того, как вы внесли необходимые изменения или тщательно изучили свои данные, убедитесь, что вы сохранили внесенные изменения. Сделав это, вы можете вернуться к данным позже, чтобы отредактировать их, добавить дополнительные данные или изменить их, сохранив формулы, которые вы, возможно, использовали для расчета данных и т.д.

Если вы работаете с Microsoft Excel, вы можете сохранить файл в разных форматах: помимо расширения по умолчанию .xls или .xlsx, вы можете перейти на вкладку «Файл», нажать «Сохранить как» и выбрать одно из расширений, которые указаны в качестве параметров «Сохранить как тип». Наиболее часто используемые расширения для сохранения наборов данных в data science — это .csv и .txt (в виде текстового файла с разделителями табуляции). В зависимости от выбранного варианта сохранения поля вашего набора данных разделяются вкладками или запятыми, которые образуют символы-разделители полей вашего набора данных.

Теперь, когда вы проверили и сохранили ваши данные, вы можете начать с подготовки вашего рабочего окружения.

Готовим рабочее окружение

Как убедиться, что вы все делаете хорошо? Проверить рабочее окружение!

Когда вы работаете в терминале, вы можете сначала перейти в каталог, в котором находится ваш файл, а затем запустить Python. Убедитесь, что файл лежит именно в том каталоге, к которому вы обратились.

Возможно, вы уже начали сеанс Python и у вас нет подсказок о каталоге, в котором вы работаете. Тогда можно выполнить следующие команды:

# Import `os` 
import os

# Retrieve current working directory (`cwd`)
cwd = os.getcwd()
cwd

# Change directory 
os.chdir("/path/to/your/folder")

# List all files and directories in current directory
os.listdir('.')

Круто, да?

Вы увидите, что эти команды очень важны не только для загрузки ваших данных, но и для дальнейшего анализа. А пока давайте продолжим: вы прошли все проверки, вы сохранили свои данные и подготовили рабочее окружение.

Можете ли вы начать с чтения данных в Python?

Установите библиотеки для чтения и записи файлов Excel

Даже если вы еще не знаете, какие библиотеки вам понадобятся для импорта ваших данных, вы должны убедиться, что у вас есть все, что нужно для установки этих библиотек, когда придет время.

Подготовка к дополнительной рабочей области: pip

Вот почему вам нужно установить pip и setuptools. Если у вас установлен Python2 ⩾ 2.7.9 или Python3  ⩾ 3.4, то можно не беспокоиться — просто убедитесь, что вы обновились до последней версии.

Для этого выполните следующую команду в своем терминале:

# Для Linux/OS X
pip install -U pip setuptools

# Для Windows
python -m pip install -U pip setuptools

Если вы еще не установили pip, запустите скрипт python get-pip.py, который вы можете найти здесь. Следуйте инструкциям по установке.

Установка Anaconda

Другой вариант для работы в data science — установить дистрибутив Anaconda Python. Сделав это, вы получите простой и быстрый способ начать заниматься data science, потому что вам не нужно беспокоиться об установке отдельных библиотек, необходимых для работы.

Это особенно удобно, если вы новичок, но даже для более опытных разработчиков это способ быстро протестировать некоторые вещи без необходимости устанавливать каждую библиотеку отдельно.

Anaconda включает в себя 100 самых популярных библиотек Python, R и Scala для науки о данных и несколько сред разработки с открытым исходным кодом, таких как Jupyter и Spyder.

Установить Anaconda можно здесь. Следуйте инструкциям по установке, и вы готовы начать!

Загрузить файлы Excel в виде фреймов Pandas

Все, среда настроена, вы готовы начать импорт ваших файлов.

Один из способов, который вы часто используете для импорта ваших файлов для обработки данных, — с помощью библиотеки Pandas. Она основана на NumPy и предоставляет простые в использовании структуры данных и инструменты анализа данных Python.

Эта мощная и гибкая библиотека очень часто используется дата-инженерами для передачи своих данных в структуры данных, очень выразительных для их анализа.

Если у вас уже есть Pandas, доступные через Anaconda, вы можете просто загрузить свои файлы в Pandas DataFrames с помощью pd.Excelfile():

# импорт библиотеки pandas
import pandas as pd

# Загружаем ваш файл в переменную `file` / вместо 'example' укажите название свого файла из текущей директории
file = 'example.xlsx'

# Загружаем spreadsheet в объект pandas
xl = pd.ExcelFile(file)

# Печатаем название листов в данном файле
print(xl.sheet_names)

# Загрузить лист в DataFrame по его имени: df1
df1 = xl.parse('Sheet1')

Если вы не установили Anaconda, просто выполните pip install pandas, чтобы установить библиотеку Pandas в вашей среде, а затем выполните команды, которые включены в фрагмент кода выше.

Проще простого, да?

Для чтения в файлах .csv у вас есть аналогичная функция для загрузки данных в DataFrame: read_csv(). Вот пример того, как вы можете использовать эту функцию:

# Импорт библиотеки pandas
import pandas as pd

# Загрузить csv файл
df = pd.read_csv("example.csv") 

Разделитель, который будет учитывать эта функция, по умолчанию является запятой, но вы можете указать альтернативный разделитель, если хотите. Перейдите к документации, чтобы узнать, какие другие аргументы вы можете указать для успешного импорта!

Обратите внимание, что есть также функции read_table() и read_fwf() для чтения файлов и таблиц с фиксированной шириной в формате DataFrames с общим разделителем. Для первой функции разделителем по умолчанию является вкладка, но вы можете снова переопределить это, а также указать альтернативный символ-разделитель. Более того, есть и другие функции, которые вы можете использовать для получения данных в DataFrames: вы можете найти их здесь.

Как записать Pandas DataFrames в файлы Excel

Допустим, что после анализа данных вы хотите записать данные обратно в новый файл. Есть также способ записать ваши Pandas DataFrames обратно в файлы с помощью функции to_excel().

Но, прежде чем использовать эту функцию, убедитесь, что у вас установлен XlsxWriter, если вы хотите записать свои данные в несколько листов в файле .xlsx:

# Установим `XlsxWriter` 
pip install XlsxWriter

# Указать writer библиотеки
writer = pd.ExcelWriter('example.xlsx', engine='xlsxwriter')

# Записать ваш DataFrame в файл     
yourData.to_excel(writer, 'Sheet1')

# Сохраним результат 
writer.save()

Обратите внимание, что в приведенном выше фрагменте кода вы используете объект ExcelWriter для вывода DataFrame.

Иными словами, вы передаете переменную Writer в функцию to_excel() и также указываете имя листа. Таким образом, вы добавляете лист с данными в существующую рабочую книгу: вы можете использовать ExcelWriter для сохранения нескольких (немного) разных DataFrames в одной рабочей книге.

Все это означает, что если вы просто хотите сохранить один DataFrame в файл, вы также можете обойтись без установки пакета XlsxWriter. Затем вы просто не указываете аргумент движка, который вы передаете в функцию pd.ExcelWriter(). Остальные шаги остаются прежними.

Аналогично функциям, которые вы использовали для чтения в файлах .csv, у вас также есть функция to_csv() для записи результатов обратно в файл, разделенный запятыми. Он снова работает так же, как когда вы использовали его для чтения в файле:

# Запишите DataFrame в csv
df.to_csv("example.csv")

Если вы хотите иметь файл, разделенный табуляцией, вы также можете передать t аргументу sep. Обратите внимание, что есть другие функции, которые вы можете использовать для вывода ваших файлов. Вы можете найти их все здесь.

Пакеты для разбора файлов Excel и обратной записи с помощью Python

Помимо библиотеки Pandas, который вы будете использовать очень часто для загрузки своих данных, вы также можете использовать другие библиотеки для получения ваших данных в Python. Наш обзор основан на этой странице со списком доступных библиотек, которые вы можете использовать для работы с файлами Excel в Python.

Далее вы увидите, как использовать эти библиотеки с помощью некоторых реальных, но упрощенных примеров.

Использование виртуальных сред

Общий совет для установки — делать это в Python virtualenv без системных пакетов. Вы можете использовать virtualenv для создания изолированных сред Python: он создает папку, содержащую все необходимые исполняемые файлы для использования пакетов, которые потребуются проекту Python.

Чтобы начать работать с virtualenv, вам сначала нужно установить его. Затем перейдите в каталог, в который вы хотите поместить свой проект. Создайте virtualenv в этой папке и загрузите в определенную версию Python, если вам это нужно. Затем вы активируете виртуальную среду. После этого вы можете начать загрузку в другие библиотеки, начать работать с ними и т. д.

Совет: не забудьте деактивировать среду, когда закончите!

# Install virtualenv
$ pip install virtualenv

# Go to the folder of your project
$ cd my_folder

# Create a virtual environment `venv`
$ virtualenv venv

# Indicate the Python interpreter to use for `venv`
$ virtualenv -p /usr/bin/python2.7 venv

# Activate `venv`
$ source venv/bin/activate

# Deactivate `venv`
$ deactivate

Обратите внимание, что виртуальная среда может показаться немного проблемной на первый взгляд, когда вы только начинаете работать с данными с Python. И, особенно если у вас есть только один проект, вы можете не понять, зачем вам вообще нужна виртуальная среда.

С ней будет гораздо легче, когда у вас одновременно запущено несколько проектов, и вы не хотите, чтобы они использовали одну и ту же установку Python. Или когда ваши проекты имеют противоречащие друг другу требования, виртуальная среда пригодится!

Теперь вы можете, наконец, начать установку и импорт библиотек, о которых вы читали, и загрузить их в таблицу.

Как читать и записывать файлы Excel с openpyxl

Этот пакет обычно рекомендуется, если вы хотите читать и записывать файлы .xlsx, xlsm, xltx и xltm.

Установите openpyxl с помощью pip: вы видели, как это сделать в предыдущем разделе.

Общий совет для установки этой библиотеки — делать это в виртуальной среде Python без системных библиотек. Вы можете использовать виртуальную среду для создания изолированных сред Python: она создает папку, которая содержит все необходимые исполняемые файлы для использования библиотек, которые потребуются проекту Python.

Перейдите в каталог, в котором находится ваш проект, и повторно активируйте виртуальную среду venv. Затем продолжите установку openpyxl с pip, чтобы убедиться, что вы можете читать и записывать файлы с ним:

# Активируйте virtualenv
$ source activate venv

# Установим `openpyxl` в `venv`
$ pip install openpyxl

Теперь, когда вы установили openpyxl, вы можете загружать данные. Но что это за данные?

Доспутим Excel с данными, которые вы пытаетесь загрузить в Python, содержит следующие листы:

Функция load_workbook() принимает имя файла в качестве аргумента и возвращает объект рабочей книги, который представляет файл. Вы можете проверить это, запустив type (wb). Убедитесь, что вы находитесь в том каталоге, где находится ваша таблица, иначе вы получите error при импорте.

# Import `load_workbook` module from `openpyxl`
from openpyxl import load_workbook

# Load in the workbook
wb = load_workbook('./test.xlsx')

# Get sheet names
print(wb.get_sheet_names())

Помните, что вы можете изменить рабочий каталог с помощью os.chdir().

Вы видите, что фрагмент кода выше возвращает имена листов книги, загруженной в Python.Можете использовать эту информацию, чтобы также получить отдельные листы рабочей книги.

Вы также можете проверить, какой лист в настоящее время активен с wb.active. Как видно из кода ниже, вы можете использовать его для загрузки другого листа из вашей книги:

# Get a sheet by name 
sheet = wb.get_sheet_by_name('Sheet3')

# Print the sheet title 
sheet.title

# Get currently active sheet
anotherSheet = wb.active

# Check `anotherSheet` 
anotherSheet

На первый взгляд, с этими объектами рабочего листа вы не сможете многое сделать.. Однако вы можете извлечь значения из определенных ячеек на листе вашей книги, используя квадратные скобки [], в которые вы передаете точную ячейку, из которой вы хотите получить значение.

Обратите внимание, что это похоже на выбор, получение и индексирование массивов NumPy и Pandas DataFrames, но это не все, что вам нужно сделать, чтобы получить значение. Вам нужно добавить атрибут value:

# Retrieve the value of a certain cell
sheet['A1'].value

# Select element 'B2' of your sheet 
c = sheet['B2']

# Retrieve the row number of your element
c.row

# Retrieve the column letter of your element
c.column

# Retrieve the coordinates of the cell 
c.coordinate

Как вы можете видеть, помимо значения, есть и другие атрибуты, которые вы можете использовать для проверки вашей ячейки, а именно: row, column и coordinate.

Атрибут row вернет 2;

Добавление атрибута column к c даст вам ‘B’

coordinate вернет ‘B2’.

Вы также можете получить значения ячеек с помощью функции cell(). Передайте row и column, добавьте к этим аргументам значения, соответствующие значениям ячейки, которую вы хотите получить, и, конечно же, не забудьте добавить атрибут value:

# Retrieve cell value 
sheet.cell(row=1, column=2).value

# Print out values in column 2 
for i in range(1, 4):
     print(i, sheet.cell(row=i, column=2).value)

Обратите внимание, что если вы не укажете атрибут value, вы получите <Cell Sheet3.B1>, который ничего не говорит о значении, которое содержится в этой конкретной ячейке.

Вы видите, что вы используете цикл for с помощью функции range(), чтобы помочь вам распечатать значения строк, имеющих значения в столбце 2. Если эти конкретные ячейки пусты, вы просто вернете None. Если вы хотите узнать больше о циклах for, пройдите наш курс Intermediate Python для Data Science.

Есть специальные функции, которые вы можете вызывать для получения некоторых других значений, например, get_column_letter() и column_index_from_string.

Две функции указывают примерно то, что вы можете получить, используя их, но лучше сделать их четче: хотя вы можете извлечь букву столбца с предшествующего, вы можете сделать обратное или получить адрес столбца, когда вы задаёте букву последнему. Вы можете увидеть, как это работает ниже:

# Импорт необходимых модулей из  `openpyxl.utils`
from openpyxl.utils import get_column_letter, column_index_from_string

# Вывод 'A'
get_column_letter(1)

# Return '1'
column_index_from_string('A')

Вы уже получили значения для строк, которые имеют значения в определенном столбце, но что вам нужно сделать, если вы хотите распечатать строки вашего файла, не сосредотачиваясь только на одном столбце? Использовать другой цикл, конечно!

Например, вы говорите, что хотите сфокусироваться на области между «А1» и «С3», где первая указывает на левый верхний угол, а вторая — на правый нижний угол области, на которой вы хотите сфокусироваться. ,

Эта область будет так называемым cellObj, который вы видите в первой строке кода ниже. Затем вы говорите, что для каждой ячейки, которая находится в этой области, вы печатаете координату и значение, которое содержится в этой ячейке. После конца каждой строки вы печатаете сообщение, которое указывает, что строка этой области cellObj напечатана.

# Напечатать строчку за строчкой
for cellObj in sheet['A1':'C3']:
      for cell in cellObj:
              print(cells.coordinate, cells.value)
      print('--- END ---')

Еще раз обратите внимание, что выбор области очень похож на выбор, получение и индексирование списка и элементов массива NumPy, где вы также используете [] и : для указания области, значения которой вы хотите получить. Кроме того, вышеприведенный цикл также хорошо использует атрибуты ячейки!

Чтобы сделать вышеприведенное объяснение и код наглядным, вы можете проверить результат, который вы получите после завершения цикла:

('A1', u'M')
('B1', u'N')
('C1', u'O')
--- END ---
('A2', 10L)
('B2', 11L)
('C2', 12L)
--- END ---
('A3', 14L)
('B3', 15L)
('C3', 16L)
--- END ---

Наконец, есть некоторые атрибуты, которые вы можете использовать для проверки результата вашего импорта, а именно max_row и max_column. Эти атрибуты, конечно, и так  — общие способы проверки правильности загрузки данных, но они все равно полезны.

# Вывести максимальное количество строк 
sheet.max_row

# Вывести максимальное количество колонок 
sheet.max_column

Наверное, вы думаете, что такой способ работы с этими файлами сложноват, особенно если вы еще хотите манипулировать данными.

Должно быть что-то попроще, верно? Так и есть!

openpyxl поддерживает Pandas DataFrames! Вы можете использовать функцию DataFrame() из библиотеки Pandas, чтобы поместить значения листа в DataFrame:

# Import `pandas` 
import pandas as pd

# конвертировать Лист в DataFrame
df = pd.DataFrame(sheet.values)

Если вы хотите указать заголовки и индексы, вам нужно добавить немного больше кода:

# Put the sheet values in `data`
data = sheet.values

# Indicate the columns in the sheet values
cols = next(data)[1:]

# Convert your data to a list
data = list(data)

# Read in the data at index 0 for the indices
idx = [r[0] for r in data]

# Slice the data at index 1 
data = (islice(r, 1, None) for r in data)

# Make your DataFrame
df = pd.DataFrame(data, index=idx, columns=cols)

Затем вы можете начать манипулировать данными со всеми функциями, которые предлагает библиотека Pandas. Но помните, что вы находитесь в виртуальной среде, поэтому, если библиотека еще не представлена, вам нужно будет установить ее снова через pip.

Чтобы записать ваши Pandas DataFrames обратно в файл Excel, вы можете легко использовать функцию dataframe_to_rows() из модуля utils:

# Import `dataframe_to_rows`
from openpyxl.utils.dataframe import dataframe_to_rows

# Initialize a workbook 
wb = Workbook()

# Get the worksheet in the active workbook
ws = wb.active

# Append the rows of the DataFrame to your worksheet
for r in dataframe_to_rows(df, index=True, header=True):
    ws.append(r)

Но это точно не все! Библиотека openpyxl предлагает вам высокую гибкость при записи ваших данных обратно в файлы Excel, изменении стилей ячеек или использовании режима write-only. Эту библиотеку обязательно нужно знать, когда вы часто работаете с электронными таблицами ,

Совет: читайте больше о том, как вы можете изменить стили ячеек, перейти в режим write-only или как библиотека работает с NumPy здесь.

Теперь давайте также рассмотрим некоторые другие библиотеки, которые вы можете использовать для получения данных вашей электронной таблицы в Python.

Прежде чем закрыть этот раздел, не забудьте отключить виртуальную среду, когда закончите!

Чтение и форматирование Excel-файлов: xlrd

Эта библиотека идеально подходит для чтения и форматирования данных из Excel с расширением xls или xlsx.

# Import `xlrd`
import xlrd

# Open a workbook 
workbook = xlrd.open_workbook('example.xls')

# Loads only current sheets to memory
workbook = xlrd.open_workbook('example.xls', on_demand = True)

Когда вам не нужны данные из всей Excel-книги, вы можете использовать функции sheet_by_name() или sheet_by_index() для получения листов, которые вы хотите получить в своём анализе

# Load a specific sheet by name
worksheet = workbook.sheet_by_name('Sheet1')

# Load a specific sheet by index 
worksheet = workbook.sheet_by_index(0)

# Retrieve the value from cell at indices (0,0) 
sheet.cell(0, 0).value

Также можно получить значение в определённых ячейках с вашего листа.

Перейдите к xlwt и xlutils, чтобы узнать больше о том, как они относятся к библиотеке xlrd.

Запись данных в Excel-файлы с xlwt

Если вы хотите создать таблицу со своими данными, вы можете использовать не только библиотеку XlsWriter, но и xlwt. xlwt идеально подходит для записи данных и форматирования информации в файлах с расширением .xls

Когда вы вручную создаёте файл:

# Import `xlwt` 
import xlwt

# Initialize a workbook 
book = xlwt.Workbook(encoding="utf-8")

# Add a sheet to the workbook 
sheet1 = book.add_sheet("Python Sheet 1") 

# Write to the sheet of the workbook 
sheet1.write(0, 0, "This is the First Cell of the First Sheet") 

# Save the workbook 
book.save("spreadsheet.xls")

Если вы хотите записать данные в файл, но не хотите делать все самостоятельно, вы всегда можете прибегнуть к циклу for, чтобы автоматизировать весь процесс. Составьте сценарий, в котором вы создаёте книгу и в которую добавляете лист. Укажите список со столбцами и один со значениями, которые будут заполнены на листе.

Далее у вас есть цикл for, который гарантирует, что все значения попадают в файл: вы говорите, что для каждого элемента в диапазоне от 0 до 4 (5 не включительно) вы собираетесь что-то делать. Вы будете заполнять значения построчно. Для этого вы указываете элемент строки, который появляется в каждом цикле. Далее у вас есть еще один цикл for, который будет проходить по столбцам вашего листа. Вы говорите, что для каждой строки на листе, вы будете смотреть на столбцы, которые идут с ним, и вы будете заполнять значение для каждого столбца в строке. Заполнив все столбцы строки значениями, вы перейдете к следующей строке, пока не останется строк.

# Initialize a workbook
book = xlwt.Workbook()

# Add a sheet to the workbook
sheet1 = book.add_sheet("Sheet1")

# The data
cols = ["A", "B", "C", "D", "E"]
txt = [0,1,2,3,4]

# Loop over the rows and columns and fill in the values
for num in range(5):
      row = sheet1.row(num)
      for index, col in enumerate(cols):
          value = txt[index] + num
          row.write(index, value)

# Save the result
book.save("test.xls")

На скриншоте ниже представлен результат выполнения этого кода:

Теперь, когда вы увидели, как xlrd и xlwt работают друг с другом, пришло время взглянуть на библиотеку, которая тесно связана с этими двумя: xlutils.

Сборник утилит: xlutils

Эта библиотека — сборник утилит, для которого требуются и xlrd и xlwt, и которая может копировать, изменять и фильтровать существующие данные. О том, как пользоваться этими командами рассказано в разделе по openpyxl.

Вернитесь в раздел openpyxl, чтобы получить больше информации о том, как использовать этот пакет для получения данных в Python.

Использование pyexcel для чтения .xls или .xlsx файлов

Еще одна библиотека, которую можно использовать для чтения данных электронных таблиц в Python — это pyexcel; Python Wrapper, который предоставляет один API для чтения, записи и работы с данными в файлах .csv, .ods, .xls, .xlsx и .xlsm. Конечно, для этого урока вы просто сосредоточитесь на файлах .xls и .xls.

Чтобы получить ваши данные в массиве, вы можете использовать функцию get_array(), которая содержится в пакете pyexcel:

# Import `pyexcel`
import pyexcel

# Get an array from the data
my_array = pyexcel.get_array(file_name="test.xls")

Вы также можете получить свои данные в упорядоченном словаре списков. Вы можете использовать функцию get_dict():

# Import `OrderedDict` module 
from pyexcel._compact import OrderedDict

# Get your data in an ordered dictionary of lists
my_dict = pyexcel.get_dict(file_name="test.xls", name_columns_by_row=0)

# Get your data in a dictionary of 2D arrays
book_dict = pyexcel.get_book_dict(file_name="test.xls")

Здесь видно, что если вы хотите получить словарь двумерных массивов или получить все листы рабочей книги в одном словаре, вы можете прибегнуть к get_book_dict().

Помните, что эти две структуры данных, которые были упомянуты выше, массивы и словари вашей таблицы, позволяют вам создавать DataFrames ваших данных с помощью pd.DataFrame(). Это облегчит обработку данных.

Кроме того, вы можете просто получить записи из таблицы с помощью pyexcel благодаря функции get_records(). Просто передайте аргумент file_name в функцию, и вы получите список словарей:

# Retrieve the records of the file
records = pyexcel.get_records(file_name="test.xls")

Чтобы узнать, как управлять списками Python, ознакомьтесь с примерами из документации о списках Python.

Запись в файл с pyexcel

С помощью этой библиотеки можно не только загружать данные в массивы, вы также можете экспортировать свои массивы обратно в таблицу. Используйте функцию save_as() и передайте массив и имя файла назначения в аргумент dest_file_name:

# Get the data
data = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]

# Save the array to a file
pyexcel.save_as(array=data, dest_file_name="array_data.xls")

Обратите внимание, что если вы хотите указать разделитель, вы можете добавить аргумент dest_delimiter и передать символ, который вы хотите использовать в качестве разделителя между «».

Однако если у вас есть словарь, вам нужно использовать функцию save_book_as(). Передайте двумерный словарь в bookdict и укажите имя файла:

# The data
2d_array_dictionary = {'Sheet 1': [
                                   ['ID', 'AGE', 'SCORE']
                                   [1, 22, 5],
                                   [2, 15, 6],
                                   [3, 28, 9]
                                  ],
                       'Sheet 2': [
                                    ['X', 'Y', 'Z'],
                                    [1, 2, 3],
                                    [4, 5, 6]
                                    [7, 8, 9]
                                  ],
                       'Sheet 3': [
                                    ['M', 'N', 'O', 'P'],
                                    [10, 11, 12, 13],
                                    [14, 15, 16, 17]
                                    [18, 19, 20, 21]
                                   ]}

# Save the data to a file                        
pyexcel.save_book_as(bookdict=2d_array_dictionary, dest_file_name="2d_array_data.xls")

При использовании кода, напечатанного в приведенном выше примере, важно помнить, что порядок ваших данных в словаре не будет сохранен. Если вы не хотите этого, вам нужно сделать небольшой обход. Вы можете прочитать все об этом здесь.

Чтение и запись .csv файлов

Если вы все еще ищете библиотеки, которые позволяют загружать и записывать данные в файлы .csv, кроме Pandas, лучше всего использовать пакет csv:

# import `csv`
import csv

# Read in csv file 
for row in csv.reader(open('data.csv'), delimiter=','):
      print(row)
      
# Write csv file
data = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
outfile = open('data.csv', 'w')
writer = csv.writer(outfile, delimiter=';', quotechar='"')
writer.writerows(data)
outfile.close()

Обратите внимание, что в пакете NumPy есть функция genfromtxt(), которая позволяет загружать данные, содержащиеся в файлах .csv, в массивы, которые затем можно поместить в DataFrames.

Финальная проверка данных

Когда у вас есть данные, не забудьте последний шаг: проверить, правильно ли загружены данные. Если вы поместили свои данные в DataFrame, вы можете легко и быстро проверить, был ли импорт успешным, выполнив следующие команды:

# Check the first entries of the DataFrame
df1.head()

# Check the last entries of the DataFrame
df1.tail()

Если у вас есть данные в массиве, вы можете проверить их, используя следующие атрибуты массива: shape, ndim, dtype и т.д .:

# Inspect the shape 
data.shape

# Inspect the number of dimensions
data.ndim

# Inspect the data type
data.dtype

Что дальше?

Поздравляем! Вы успешно прошли наш урок и научились читать файлы Excel на Python.

Если вы хотите продолжить работу над этой темой, попробуйте воспользоваться PyXll, который позволяет писать функции в Python и вызывать их в Excel.

How to create, read, update and search through Excel files using Python

This article will show in detail how to work with Excel files and how to modify specific data with Python.

First we will learn how to work with CSV files by reading, writing and updating them. Then we will take a look how to read files, filter them by sheets, search for rows/columns, and update cells of xlsx files.

Let’s start with the simplest spreadsheet format: CSV.

Part 1 — The CSV file

A CSV file is a comma-separated values file, where plain text data is displayed in a tabular format. They can be used with any spreadsheet program, such as Microsoft Office Excel, Google Spreadsheets, or LibreOffice Calc.

CSV files are not like other spreadsheet files though, because they don’t allow you to save cells, columns, rows or formulas. Their limitation is that they also allow only one sheet per file. My plan for this first part of the article is to show you how to create CSV files using Python 3 and the standard library module CSV.

This tutorial will end with two GitHub repositories and a live web application that actually uses the code of the second part of this tutorial (yet updated and modified to be for a specific purpose).

Writing to CSV files

First, open a new Python file and import the Python CSV module.

import csv

CSV Module

The CSV module includes all the necessary methods built in. These include:

  • csv.reader
  • csv.writer
  • csv.DictReader
  • csv.DictWriter
  • and others

In this guide we are going to focus on the writer, DictWriter and DictReader methods. These allow you to edit, modify, and manipulate the data stored in a CSV file.

In the first step we need to define the name of the file and save it as a variable. We should do the same with the header and data information.

filename = "imdb_top_4.csv"
header = ("Rank", "Rating", "Title")
data = [
(1, 9.2, "The Shawshank Redemption(1994)"),
(2, 9.2, "The Godfather(1972)"),
(3, 9, "The Godfather: Part II(1974)"),
(4, 8.9, "Pulp Fiction(1994)")
]

Now we need to create a function named writer that will take in three parameters: header, data and filename.

def writer(header, data, filename):
  pass

The next step is to modify the writer function so it creates a file that holds data from the header and data variables. This is done by writing the first row from the header variable and then writing four rows from the data variable (there are four rows because there are four tuples inside the list).

def writer(header, data, filename):
  with open (filename, "w", newline = "") as csvfile:
    movies = csv.writer(csvfile)
    movies.writerow(header)
    for x in data:
      movies.writerow(x)

The official Python documentation describes how the csv.writer method works. I would strongly suggest that you to take a minute to read it.

And voilà! You created your first CSV file named imdb_top_4.csv. Open this file with your preferred spreadsheet application and you should see something like this:

1*DuYsqu8EFzU15u_0HgNDKg

Using LibreOffice Calc to see the result.

The result might be written like this if you choose to open the file in some other application:

1*Q0U_MBj6mr3ekidC299lbQ

Using SublimeText to see the result.

Updating the CSV files

To update this file you should create a new function named updater that will take just one parameter called filename.

def updater(filename):
    with open(filename, newline= "") as file:
        readData = [row for row in csv.DictReader(file)]
        # print(readData)
        readData[0]['Rating'] = '9.4'
        # print(readData)

    readHeader = readData[0].keys()
    writer(readHeader, readData, filename, "update")

This function first opens the file defined in the filename variable and then saves all the data it reads from the file inside of a variable named readData. The second step is to hard code the new value and place it instead of the old one in the readData[0][‘Rating’] position.

The last step in the function is to call the writer function by adding a new parameter update that will tell the function that you are doing an update.

csv.DictReader is explained more in the official Python documentation here.

For writer to work with a new parameter, you need to add a new parameter everywhere writer is defined. Go back to the place where you first called the writer function and add “write” as a new parameter:

writer(header, data, filename, "write")

Just below the writer function call the updater and pass the filename parameter into it:

writer(header, data, filename, "write")
updater(filename)

Now you need to modify the writer function to take a new parameter named option:

def writer(header, data, filename, option):

From now on we expect to receive two different options for the writer function (write and update). Because of that we should add two if statements to support this new functionality. First part of the function under “if option == “write:” is already known to you. You just need to add the “elif option == “update”: section of the code and the else part just as they are written bellow:

def writer(header, data, filename, option):
        with open (filename, "w", newline = "") as csvfile:
            if option == "write":

                movies = csv.writer(csvfile)
                movies.writerow(header)
                for x in data:
                    movies.writerow(x)
            elif option == "update":
                writer = csv.DictWriter(csvfile, fieldnames = header)
                writer.writeheader()
                writer.writerows(data)
            else:
                print("Option is not known")

Bravo! Your are done!

Now your code should look something like this:

0*vPoREgLGJU8VmB5k

The code.

You can also find the code here:

https://github.com/GoranAviani/CSV-Viewer-and-Editor

In the first part of this article we have seen how to work with CSV files. We have created and updated one such file.

Part 2 — The xlsx file

For several weekends I have worked on this project. I have started working on it because there was a need for this kind of solution in my company. My first idea was to build this solution directly in my company’s system, but then I wouldn’t have anything to write about, eh?

I build this solution using Python 3 and openpyxl library. The reason why I have chosen openpyxl is because it represents a complete solution for creating worksheets, loading, updating, renaming and deleting them. It also allows us to read or write to rows and columns, merge or un-merge cells or create Python excel charts etc.

Openpyxl terminology and basic info

  • Workbook is the name for an Excel file in Openpyxl.
  • A workbook consists of sheets (default is 1 sheet). Sheets are referenced by their names.
  • A sheet consists of rows (horizontal lines) starting from the number 1 and columns (vertical lines) starting from the letter A.
  • Rows and columns result in a grid and form cells which may contain some data (numerical or string value) or formulas.

Openpyxl in nicely documented and I would advise that you take a look here.

The first step is to open your Python environment and install openpyxl within your terminal:

pip install openpyxl

Next, import openpyxl into your project and then to load a workbook into the theFile variable.

import openpyxl

theFile = openpyxl.load_workbook('Customers1.xlsx')
print(theFile.sheetnames)
currentSheet = theFile['customers 1']
print(currentSheet['B4'].value)

As you can see, this code prints all sheets by their names. It then selects the sheet that is named “customers 1” and saves it to a currentSheet variable. In the last line, the code prints the value that is located in the B4 position of the “customers 1” sheet.

This code works as it should but it is very hard coded. To make this more dynamic we will write code that will:

  • Read the file
  • Get all sheet names
  • Loop through all sheets
  • In the last step, the code will print values that are located in B4 fields of each found sheet inside the workbook.
import openpyxl

theFile = openpyxl.load_workbook('Customers1.xlsx')
allSheetNames = theFile.sheetnames

print("All sheet names {} " .format(theFile.sheetnames))


for x in allSheetNames:
    print("Current sheet name is {}" .format(x))
    currentSheet = theFile[x]
    print(currentSheet['B4'].value)

This is better than before, but it is still a hard coded solution and it still assumes the value you will be looking for is in the B4 cell, which is just silly :)

I expect your project will need to search inside all sheets in the Excel file for a specific value. To do this we will add one more for loop in the “ABCDEF” range and then simply print cell names and their values.

import openpyxl

theFile = openpyxl.load_workbook('Customers1.xlsx')
allSheetNames = theFile.sheetnames

print("All sheet names {} " .format(theFile.sheetnames))


for sheet in allSheetNames:
    print("Current sheet name is {}" .format(sheet))
    currentSheet = theFile[sheet]
    # print(currentSheet['B4'].value)

    #print max numbers of wors and colums for each sheet
    #print(currentSheet.max_row)
    #print(currentSheet.max_column)

    for row in range(1, currentSheet.max_row + 1):
        #print(row)
        for column in "ABCDEF":  # Here you can add or reduce the columns
            cell_name = "{}{}".format(column, row)
            #print(cell_name)
            print("cell position {} has value {}".format(cell_name, currentSheet[cell_name].value))

We did this by introducing the “for row in range..” loop. The range of the for loop is defined from the cell in row 1 to the sheet’s maximum number or rows. The second for loop searches within predefined column names “ABCDEF”. In the second loop we will display the full position of the cell (column name and row number) and a value.

However, in this article my task is to find a specific column that is named “telephone” and then go through all the rows of that column. To do that we need to modify the code like below.

import openpyxl

theFile = openpyxl.load_workbook('Customers1.xlsx')
allSheetNames = theFile.sheetnames

print("All sheet names {} " .format(theFile.sheetnames))


def find_specific_cell():
    for row in range(1, currentSheet.max_row + 1):
        for column in "ABCDEFGHIJKL":  # Here you can add or reduce the columns
            cell_name = "{}{}".format(column, row)
            if currentSheet[cell_name].value == "telephone":
                #print("{1} cell is located on {0}" .format(cell_name, currentSheet[cell_name].value))
                print("cell position {} has value {}".format(cell_name, currentSheet[cell_name].value))
                return cell_name

for sheet in allSheetNames:
    print("Current sheet name is {}" .format(sheet))
    currentSheet = theFile[sheet]

This modified code goes through all cells of every sheet, and just like before the row range is dynamic and the column range is specific. The code loops through cells and looks for a cell that holds a text “telephone”. Once the code finds the specific cell it notifies the user in which cell the text is located. The code does this for every cell inside of all sheets that are in the Excel file.

The next step is to go through all rows of that specific column and print values.

import openpyxl

theFile = openpyxl.load_workbook('Customers1.xlsx')
allSheetNames = theFile.sheetnames

print("All sheet names {} " .format(theFile.sheetnames))


def find_specific_cell():
    for row in range(1, currentSheet.max_row + 1):
        for column in "ABCDEFGHIJKL":  # Here you can add or reduce the columns
            cell_name = "{}{}".format(column, row)
            if currentSheet[cell_name].value == "telephone":
                #print("{1} cell is located on {0}" .format(cell_name, currentSheet[cell_name].value))
                print("cell position {} has value {}".format(cell_name, currentSheet[cell_name].value))
                return cell_name

def get_column_letter(specificCellLetter):
    letter = specificCellLetter[0:-1]
    print(letter)
    return letter

def get_all_values_by_cell_letter(letter):
    for row in range(1, currentSheet.max_row + 1):
        for column in letter:
            cell_name = "{}{}".format(column, row)
            #print(cell_name)
            print("cell position {} has value {}".format(cell_name, currentSheet[cell_name].value))



for sheet in allSheetNames:
    print("Current sheet name is {}" .format(sheet))
    currentSheet = theFile[sheet]
    specificCellLetter = (find_specific_cell())
    letter = get_column_letter(specificCellLetter)

    get_all_values_by_cell_letter(letter)

This is done by adding a function named get_column_letter that finds a letter of a column. After the letter of the column is found we loop through all rows of that specific column. This is done with the get_all_values_by_cell_letter function which will print all values of those cells.

Wrapping up

Bra gjort! There are many thing you can do after this. My plan was to build an online app that will standardize all Swedish telephone numbers taken from a text box and offer users the possibility to simply copy the results from the same text box. The second step of my plan was to expand the functionality of the web app to support the upload of Excel files, processing of telephone numbers inside those files (standardizing them to a Swedish format) and offering the processed files back to users.

I have done both of those tasks and you can see them live in the Tools page of my Incodaq.com site:

https://tools.incodaq.com/

Also the code from the second part of this article is available on GitHub:

https://github.com/GoranAviani/Manipulate-Excel-spreadsheets

Thank you for reading! Check out more articles like this on my Medium profile: https://medium.com/@goranaviani and other fun stuff I build on my GitHub page: https://github.com/GoranAviani



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    In this article, We are going to change the value in an Excel Spreadsheet using Python.

    Method 1: Using openxml:

    openpyxl is a Python library to read/write Excel xlsx/xlsm/xltx/xltm files. It was born from a lack of an existing library to read/write natively from Python the Office Open XML format. openpyxl is the library needed for the following task. You can install openpyxl module by using the following command in Python.

    pip install openpyxl

    Function used:

    • load_workbook(): function used to read the excel spreadsheet
    • workbook.active: points towards the active sheet in the excel spreadsheet
    • workbook.save(): saves the workbook

    Approach:

    1. Import openpyxl library
    2. Start by opening the spreadsheet and selecting the main sheet
    3. Write what you want into a specific cell
    4. Save the spreadsheet

    Excel File Used:

    Below is the implementation:

    Python3

    from openpyxl import load_workbook

    workbook = load_workbook(filename="csv/Email_sample.xlsx")

    sheet = workbook.active

    sheet["A1"] = "Full Name"

    workbook.save(filename="csv/output.xlsx")

    Output:

    Method 1: Using xlwt/xlrd/xlutils.

    This package provides a collection of utilities for working with Excel files. Since these utilities may require either or both of the xlrd and xlwt packages, they are collected together here, separate from either package.You can install xlwt/xlrd/xlutils modules by using the following command in Python

    pip install xlwt
    pip install xlrd
    pip install xlutils

    Prerequisite:

    • open_workbook(): function used to read the excel spreadsheet
    • copy(): copies the content of a workbook
    • get_sheet(): points towards a specific sheet in excel workbook
    • write(): writes data in the file
    • save(): saves the file

    Approach:

    1. Open Excel File
    2. Make a writable copy of the opened Excel file
    3. Read the first sheet to write within the writable copy
    4. Modify value at the desired location
    5. Save the workbook
    6. Run the program

    Excel File Used:

    Below is the implementation:

    Python3

    import xlwt

    import xlrd

    from xlutils.copy import copy

    rb = xlrd.open_workbook('UserBook.xls')

    wb = copy(rb)

    w_sheet = wb.get_sheet(0)

    w_sheet.write(0,1,'Modified !')

    wb.save('UserBook.xls')

    Output:

    After

    Like Article

    Save Article

    Project description

    editpyxl is a Python library to non-destructively edit Excel 2010 xlsx/xlsm files.

    The purpose is to edit excel files without otherwise modifying the excel document, to allow for efficient and quick
    edits of an excel file.

    Many thanks to openpyxl for their hard work in developing a tool to read and writing excel files.
    https://bitbucket.org/ericgazoni/openpyxl

    Official documentation

    The homepage is http://editpyxl.readthedocs.org
    You will find:

    • every installation methods

    • the official documentation

    • code examples

    • instructions for contributing

    0.1.10

    • Updated MutableSet import for python 3.10 compatibility

    0.1.9

    • Force closing of zip file before removing folder, to prevent PermissionError: [WinError 32] error.

    0.1.8

    • Added worksheet function clear_formula_values. This deletes preset values in formulas to force recalculation, to
      solve issue in Excel 2016 not respecting force recalc flags or the absence of the calcChain.xml

    0.1.5

    • Updated lxml writing for python3

    0.1.4

    • Updated uuid1().get_hex() -> uuid1().hex

    0.1.3

    • Added wb[‘sheetname’] notation.

    • Added wb.sheetnames

    0.1.2

    • Added ws[‘A1’] notation.

    0.1.1

    • Added ws.dump() to dump all cell values.

    0.1.0

    • Added wb.hide_sheet() / wb.unhide_sheet()

    0.0.9 (unreleased)

    • Fixed filename parsing.

    0.0.8 (unreleased)

    • Added function for updating formulas.

    0.0.7 (unreleased)

    • Remove formulas from cells when setting value and remove calcChain.xml.

    0.0.1 (unreleased)

    Initial Release

    • Initial project released in Alpha.

    Download files

    Download the file for your platform. If you’re not sure which to choose, learn more about installing packages.

    Source Distribution

    Built Distribution

    Microsoft Excel is probably one of the highly used data storage applications. A huge proportion of small to medium size businesses fulfill their analytics requirement using Excel.

    However, analyzing huge amount of data in Excel can become highly tedious and time-consuming. You could build customized data processing and analytics application using Visual Basic(VBA), the language that powers the Excel sheets. However, learning VBA could be difficult and perhaps, not worth it.

    However, if you have a little knowledge of Python, you could build highly professional Business Intelligence using Excel data, without the need of a database. Using Python with Excel could be a game changer for your business.

    Sections Covered

    1. Basic Information about Excel
    2. What is Openpyxl and how to install it?
    3. Reading data from Excel in Python
    4. Reading multiple cells from Excel in Python
    5. Find the max row and column number of an Excel sheet in Python
    6. How to iterate over Excel rows and columns in Python?
    7. Create a new Excel file with Python
    8. Writing data to Excel in Python
    9. Appending data to Excel in Python
    10. Manipulating Excel Sheets in Python
    11. Practical usage example of data analysis of Excel sheets in Python

    Basic Information about Excel

    Before beginning this Openpyxl tutorial, you need to keep the following details in mind.

    1. Excel files are called Workbooks.
    2. Each Workbook can contain multiple sheets.
    3. Every sheet consists of rows starting from 1 and columns starting from A.
    4. Rows and columns together make up a cell.
    5. Any type of data can be stored.

    What is Openpyxl and how to install it?

    The Openpyxl module in Python is used to handle Excel files without involving third-party Microsoft application software. It is arguably, the best python excel library that allows you to perform various Excel operations and automate excel reports using Python. You can perform all kinds of tasks using Openpyxl like:-

    1. Reading data
    2. Writing data
    3. Editing Excel files
    4. Drawing graphs and charts
    5. Working with multiple sheets
    6. Sheet Styling etc.

    You can install Openpyxl module by typing pip install openpyxl in your command line.

    pip install openpyxl

    Reading data from Excel in Python

    To import an excel file in Python, use the load_workbook method from Openpyxl library.

    Let’s import an Excel file named wb1.xlsx in Python using Openpyxl module. It has the following data as shown in the image below.

    Step 1 — Import the load_workbook method from Openpyxl.

    from openpyxl import load_workbook
    

    Step 2 — Provide the file location for the Excel file you want to open in Python.

       wb = load_workbook('wb1.xlsx')

    If your Excel file is present in the same directory as the python file, you don’t need to provide to entire file location.

    Step 3 — Choose the first active sheet present in the workbook using wb.active attribute.

       sheet = wb.active

    The above points are a standard way of accessing Excel sheets using Python. You will see them being used multiple times through out this article.

    Let’s read all the data present in Row 1 (header row).

    Method 1 — Reading data through Excel cell name in Python

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    print(sheet["A1"].value)
    print(sheet["B1"].value)
    print(sheet["C1"].value)
    print(sheet["D1"].value)

    Output

    ProductId
    ProductName
    Cost per Unit
    Quantity

    Method 2 — Reading data from Excel using cell() method in Python

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    print(sheet.cell(row=1, column=1).value)
    print(sheet.cell(row=1, column=2).value)
    print(sheet.cell(row=1, column=3).value)
    print(sheet.cell(row=1, column=4).value)

    Output

    ProductId
    ProductName
    Cost per Unit
    Quantity

    Reading Multiple Cells from Excel in Python

    You can also read multiple cells from an Excel workbook. Let’s understand this through various examples. Refer to the image of the wb1.xlsx file above for clarity.

    Method 1 — Reading a range of cells in Excel using cell names

    To read the data from a specific range of cells in your Excel sheet, you need to slice your sheet object through both the cells.

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    # Access all cells from A1 to D11
    print(sheet["A1:D11"])

    Output

    ((<Cell 'Sheet1'.A1>, <Cell 'Sheet1'.B1>, <Cell 'Sheet1'.C1>, <Cell 'Sheet1'.D1>), 
     (<Cell 'Sheet1'.A2>, <Cell 'Sheet1'.B2>, <Cell 'Sheet1'.C2>, <Cell 'Sheet1'.D2>), 
     (<Cell 'Sheet1'.A3>, <Cell 'Sheet1'.B3>, <Cell 'Sheet1'.C3>, <Cell 'Sheet1'.D3>), 
     (<Cell 'Sheet1'.A4>, <Cell 'Sheet1'.B4>, <Cell 'Sheet1'.C4>, <Cell 'Sheet1'.D4>), 
     (<Cell 'Sheet1'.A5>, <Cell 'Sheet1'.B5>, <Cell 'Sheet1'.C5>, <Cell 'Sheet1'.D5>), 
     (<Cell 'Sheet1'.A6>, <Cell 'Sheet1'.B6>, <Cell 'Sheet1'.C6>, <Cell 'Sheet1'.D6>), 
     (<Cell 'Sheet1'.A7>, <Cell 'Sheet1'.B7>, <Cell 'Sheet1'.C7>, <Cell 'Sheet1'.D7>), 
     (<Cell 'Sheet1'.A8>, <Cell 'Sheet1'.B8>, <Cell 'Sheet1'.C8>, <Cell 'Sheet1'.D8>), 
     (<Cell 'Sheet1'.A9>, <Cell 'Sheet1'.B9>, <Cell 'Sheet1'.C9>, <Cell 'Sheet1'.D9>), 
     (<Cell 'Sheet1'.A10>, <Cell 'Sheet1'.B10>, <Cell 'Sheet1'.C10>, <Cell 'Sheet1'.D10>), 
     (<Cell 'Sheet1'.A11>, <Cell 'Sheet1'.B11>, <Cell 'Sheet1'.C11>, <Cell 'Sheet1'.D11>))

    You can see that by slicing the sheet data from A1:D11, it returned us tuples of row data inside a tuple. In order to read the values of every cell returned, you can iterate over each row and use .value.

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    # Access all cells from A1 to D11
    for row in sheet["A1:D11"]:
        print ([x.value for x in row])

    Output

    ['ProductId', 'ProductName', 'Cost per Unit', 'Quantity']
    [1, 'Pencil', '$0.5', 200]
    [2, 'Pen', '$1', 500]
    [3, 'Eraser', '$0.25', 100]
    [4, 'Sharpner', '$0.75', 100]
    [5, 'Files', '$3', 50]
    [6, 'A4 Size Paper', '$9', 10]
    [7, 'Pencil Box', '$12', 20]
    [8, 'Pen Stand', '$5.5', 10]
    [9, 'Notebook', '$2', 50]
    [10, 'Marker', '$1', 75]

    Method 2 — Reading a single row in Excel using cell name

    To read a single row in your Excel sheet, just access the single row number from your sheet object.

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    # Access all cells in row 1
    for data in sheet["1"]:
        print(data.value)

    Output

    ProductId
    ProductName
    Cost per Unit
    Quantity

    Method 3 — Reading all rows in Excel using rows attribute

    To read all the rows, use sheet.rows to iterate over rows with Openpyxl. You receive a tuple element per row by using the sheet.rows attribute.

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    # Access all cells in row 1
    for row in sheet.rows:
        print([data.value for data in row])

    Output

    ['ProductId', 'ProductName', 'Cost per Unit', 'Quantity']
    [1, 'Pencil', '$0.5', 200]
    [2, 'Pen', '$1', 500]
    [3, 'Eraser', '$0.25', 100]
    [4, 'Sharpner', '$0.75', 100]
    [5, 'Files', '$3', 50]
    [6, 'A4 Size Paper', '$9', 10]
    [7, 'Pencil Box', '$12', 20]
    [8, 'Pen Stand', '$5.5', 10]
    [9, 'Notebook', '$2', 50]
    [10, 'Marker', '$1', 75]

    Method 4 — Reading a single column in Excel using cell name

    Similar to reading a single row, you can read the data in a single column of your Excel sheet by its alphabet.

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    # Access all cells in column A
    for data in sheet["A"]:
        print(data.value)

    Output

    ProductId
    1
    2
    3
    4
    5
    6
    7
    8
    9
    10

    Method 5 — Reading all the columns in Excel using columns attribute

    To read all the data as a tuple of the columns in your Excel sheet, use sheet.columns attribute to iterate over all columns with Openpyxl.

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    # Access all columns
    for col in sheet.columns:
        print([data.value for data in col])

    Output

    ['ProductId', 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
    ['ProductName', 'Pencil', 'Pen', 'Eraser', 'Sharpner', 'Files', 'A4 Size Paper', 'Pencil Box', 'Pen Stand', 'Notebook', 'Marker']
    ['Cost per Unit', '$0.5', '$1', '$0.25', '$0.75', '$3', '$9', '$12', '$5.5', '$2', '$1']
    ['Quantity', 200, 500, 100, 100, 50, 10, 20, 10, 50, 75]

    Method 6 — Reading all the data in Excel

    To read all the data present in your Excel sheet, you don’t need to index the sheet object. You can just iterate over it.

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    # Access all cells in Excel
    for row in sheet:
        print([data.value for data in row])

    Output

    ['ProductId', 'ProductName', 'Cost per Unit', 'Quantity']
    [1, 'Pencil', '$0.5', 200]
    [2, 'Pen', '$1', 500]
    [3, 'Eraser', '$0.25', 100]
    [4, 'Sharpner', '$0.75', 100]
    [5, 'Files', '$3', 50]
    [6, 'A4 Size Paper', '$9', 10]
    [7, 'Pencil Box', '$12', 20]
    [8, 'Pen Stand', '$5.5', 10]
    [9, 'Notebook', '$2', 50]
    [10, 'Marker', '$1', 75]

    Find the max row and column number of an Excel Sheet in Python

    To find the max row and column number from your Excel sheet in Python, use sheet.max_row and sheet.max_column attributes in Openpyxl.

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    print(f"Max row in the active sheet is {sheet.max_row}")
    print(f"Max column in the active sheet is {sheet.max_column}")

    Output

    Max row in the active sheet is 11
    Max column in the active sheet is 4

    Note — If you update a cell with a value, the sheet.max_row and sheet.max_column values also change, even though you haven’t saved your changes.

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('pylenin.xlsx')
    
    sheet = wb.active
    
    sheet["A1"].value = "Lenin"
    print(sheet.max_row)
    
    sheet["A2"].value = "Mishra"
    print(sheet.max_row)
    
    # wb.save('pylenin.xlsx')

    Output

    1
    2

    How to iterate over Excel rows and columns in Python?

    Openpyxl offers two commonly used methods called iter_rows and iter_cols to iterate over Excel rows and columns in Python.

    1. iter_rows() — Returns one tuple element per row selected.
    2. iter_cols() — Returns one tuple element per column selected.

    Both the above mentioned methods can receive the following arguments for setting boundaries for iteration:

    • min_row
    • max_row
    • min_col
    • max_col

    Example 1 — iter_rows()

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    # Access all cells from between 
    # "Row 1 and Row 2" and "Column 1 and Column 3"
    for row in sheet.iter_rows(min_row=1,
                               max_row=2,
                               min_col=1,
                               max_col=3):
        print([data.value for data in row])

    Output

    ['ProductId', 'ProductName', 'Cost per Unit']
    [1, 'Pencil', '$0.5']

    As you can see, only the first 3 columns of the first 2 rows are returned. The tuples are row based.

    You can also choose to not pass in some or any arguments in iter_rows method.

    Code — Not passing min_col and max_col

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    # min_col and max_col arguments are not provided
    for row in sheet.iter_rows(min_row=1,
                               max_row=2):
        print([data.value for data in row])

    Output

    ['ProductId', 'ProductName', 'Cost per Unit', 'Quantity']
    [1, 'Pencil', '$0.5', 200]

    All the columns from the first 2 rows are being printed.

    Example 2 — iter_cols()

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    # Access all cells from A1 to D11
    for row in sheet.iter_cols(min_row=1,
                               max_row=2,
                               min_col=1,
                               max_col=3):
        print([data.value for data in row])

    Output

    ['ProductId', 1]
    ['ProductName', 'Pencil']
    ['Cost per Unit', '$0.5']

    The tuples returned are column based on using iter_cols() method.

    You can also choose to not pass in some or any arguments in iter_cols() method.

    Code — Not passing any argument

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    # min_col and max_col arguments are not provided
    for row in sheet.iter_cols():
        print([data.value for data in row])

    Output

    ['ProductId', 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
    ['ProductName', 'Pencil', 'Pen', 'Eraser', 'Sharpner', 'Files', 'A4 Size Paper', 'Pencil Box', 'Pen Stand', 'Notebook', 'Marker']
    ['Cost per Unit', '$0.5', '$1', '$0.25', '$0.75', '$3', '$9', '$12', '$5.5', '$2', '$1']
    ['Quantity', 200, 500, 100, 100, 50, 10, 20, 10, 50, 75]

    Create a new Excel file with Python

    To create a new Excel file in Python, you need to import the Workbook class from Openpyxl library.

    Code

    from openpyxl import Workbook
    
    wb = Workbook()
    sheet = wb.active
    
    sheet['A1'] = "Pylenin"
    sheet['B1'] = "loves"
    sheet['C1'] = "Python"
    
    wb.save("pylenin.xlsx")

    This should create a new Excel workbook called pylenin.xlsx with the provided data.


    Writing data to Excel in Python

    There are multiple ways to write data to an Excel file in Python.

    Method 1 — Writing data to Excel using cell names

    Code

    from openpyxl import Workbook
    
    wb = Workbook()
    sheet = wb.active
    
    sheet['A1'] = "Pylenin"
    sheet['B1'] = "loves"
    sheet['C1'] = "Python"
    
    wb.save("pylenin.xlsx")

    Output

    Method 2 — Writing data to Excel using the cell() method

    Code

    from openpyxl import Workbook
    
    wb = Workbook()
    sheet = wb.active
    
    sheet.cell(row=1, column=1).value = "Pylenin"
    sheet.cell(row=1, column=2).value = "loves"
    sheet.cell(row=1, column=3).value = "Python"
    
    wb.save("pylenin.xlsx")

    Output

    Method 3 — Writing data to Excel by iterating over rows

    Code — Example 1

    from openpyxl import Workbook
    
    wb = Workbook()
    sheet = wb.active
    
    for row in sheet["A1:D3"]:
        row[0].value = "Pylenin"
        row[1].value = "loves"
        row[2].value = "Python"
    
    wb.save("pylenin.xlsx")

    Output

    You can also use methods like iter_rows() and iter_cols() to write data to Excel.

    Code — Example 2 — using iter_rows() method

    from openpyxl import Workbook
    
    wb = Workbook()
    sheet = wb.active
    
    for row in sheet.iter_rows(min_row=1,
                               max_row=3,
                               min_col=1,
                               max_col=3):
        row[0].value = "Pylenin"
        row[1].value = "loves"
        row[2].value = "Python"
    
    wb.save("pylenin.xlsx")

    Output

    Code — Example 3 — using iter_cols() method

    from openpyxl import Workbook
    
    wb = Workbook()
    sheet = wb.active
    
    for col in sheet.iter_cols(min_row=1,
                               max_row=3,
                               min_col=1,
                               max_col=3):
        col[0].value = "Pylenin"
        col[1].value = "loves"
        col[2].value = "Python"
    
    wb.save("pylenin.xlsx")

    Output


    Appending data to Excel in Python

    Openpyxl provides an append() method, which is used to append values to an existing Excel sheet in Python.

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('pylenin.xlsx')
    sheet = wb.active
    
    data = (
        ("Pylenin", "likes", "icecream"),
        ("Pylenin", "likes", "Cricket")
    )
    
    for row in data:
        sheet.append(row)
    wb.save('pylenin.xlsx')

    Output


    Manipulating Excel Sheets in Python

    Each Excel workbook can contain multiple sheets. To get a list of all the sheet names in an Excel workbook, you can use the wb.sheetnames.

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('pylenin.xlsx')
    print(wb.sheetnames)

    Output

    ['Sheet']

    As you can see, pylenin.xlsx has only one sheet.

    To create a new sheet in Python, use the create_sheet() method from the Openpyxl library.

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('pylenin.xlsx')
    wb.create_sheet('Pylenin')
    
    wb.save('pylenin.xlsx')

    Output

    You can also create sheets at different positions in the Excel Workbook.

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('pylenin.xlsx')
    
    # insert sheet at 2nd to last position
    wb.create_sheet('Lenin Mishra', -1)
    
    wb.save('pylenin.xlsx')

    Output

    If your Excel workbook contains multiple sheets and you want to work with a particular sheet, you can refer the title of that sheet in your workbook object.

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('pylenin.xlsx')
    ws = wb["Pylenin"]
    
    ws["A1"].value = "Pylenin"
    ws["A2"].value = "loves"
    ws["A3"].value = "Python"
    
    wb.save('pylenin.xlsx')

    Output


    Practical usage example of data analysis of Excel sheets in Python

    Let’s perform some data analysis with wb1.xlsx file as shown in the first image.

    Objective

    1. Add a new column showing Total Price per Product.
    2. Calculate the Total Cost of all the items bought.

    The resulting Excel sheet should look like the below image.

    Step 1 — Find the max row and max column of the Excel sheet

    As mentioned before, you can use the sheet.max_row and sheet.max_column attributes to find the max row and max column for any Excel sheet with Openpyxl.

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    print(f"Max row in the active sheet is {sheet.max_row}")
    print(f"Max column in the active sheet is {sheet.max_column}")

    Output

    Max row in the active sheet is 11
    Max column in the active sheet is 4

    Step 2 — Add an extra column in Excel with Python

    To add an extra column in the active Excel sheet, with calculations, you need to first create a new column header in the first empty cell and then iterate over all rows to multiply Quantity with Cost per Unit.

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    # Add new column header
    
    sheet.cell(row=1, column=sheet.max_column+1).value = "Total Price per Product"
    
    wb.save("wb1.xlsx")

    Output

    Now that an extra column header has been created, the sheet.max_column value will change to 5.

    Now you can calculate the Total Price per Product using iter_rows() method.

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    # Calculate Total Price per Product
    
    for id, row in enumerate(sheet.iter_rows(min_row=2,
                                             max_row = sheet.max_row)):
    
        row_number = id + 2 # index for enumerate will start at 0
        product_name = row[1].value
        cost_per_unit = row[2].value
        quantity = row[3].value
        print(f"Total cost for {product_name} is {cost_per_unit*quantity}")
    
        # Update cell value in the last column
        current_cell = sheet.cell(row=row_number, column=sheet.max_column)
        current_cell.value = cost_per_unit*quantity
    
        # Format cell from number to $ currency
        current_cell.number_format = '$#,#0.0'
    
    print("nSuccesfully updated Excel")
    wb.save('wb1.xlsx')

    Output

    Total cost for Pencil is 100.0
    Total cost for Pen is 500
    Total cost for Eraser is 25.0
    Total cost for Sharpner is 75.0
    Total cost for Files is 150
    Total cost for A4 Size Paper is 90
    Total cost for Pencil Box is 240
    Total cost for Pen Stand is 55.0
    Total cost for Notebook is 100
    Total cost for Marker is 75
    
    Succesfully updated Excel

    Step 3 — Calculate sum of a column in Excel with Python

    The last step is to calculate the Total Cost of the last column in the Excel file.

    Access the last column and add up all the cost.

    You can read the last column by accessing the sheet.columns attribute. Since it returns a generator, you first convert it to a python list and access the last column.

    last_column_data = list(sheet.columns)[-1]
    # Ignore header cell 
    total_cost = sum([x.value for x in last_column_data[1:]])

    Create a new row 2 places down from the max_row and fill in Total Cost.

    max_row = sheet.max_row
        
    total_cost_descr_cell = sheet.cell(row = max_row +2, column = sheet.max_column -1)
    total_cost_descr_cell.value = "Total Cost"
         
    total_cost_cell =  sheet.cell(row = max_row +2, column = sheet.max_column)
    total_cost_cell.value = total_cost

    Import Font class from openpyxl.styles to make the last row Bold.

    # Import the Font class from Openpyxl
    from openpyxl.styles import Font
        
    bold_font = Font(bold=True)
    total_cost_descr_cell.font = bold_font
    total_cost_cell.font = bold_font
        
    total_cost_cell.number_format = "$#,#0.0"

    Final Code

    Code

    from openpyxl import load_workbook
    
    wb = load_workbook('wb1.xlsx')
    
    sheet = wb.active
    
    last_column_data = list(sheet.columns)[-1]
    # Ignore header cell 
    total_cost = sum([x.value for x in last_column_data[1:]])
    
    max_row = sheet.max_row
    
    total_cost_descr_cell = sheet.cell(row = max_row + 2, column = sheet.max_column -1)
    total_cost_descr_cell.value = "Total Cost"
    
    total_cost_cell =  sheet.cell(row = max_row + 2, column = sheet.max_column)
    total_cost_cell.value = total_cost
    
    # Import the Font class from Openpyxl
    from openpyxl.styles import Font
    
    bold_font = Font(bold=True)
    total_cost_descr_cell.font = bold_font
    total_cost_cell.font = bold_font
    
    total_cost_cell.number_format = "$#,#0.0"
    
    print("nSuccesfully updated Excel")
    wb.save('wb1.xlsx')

    When you run the above code, you should see all the relevant updates to your Excel sheet.

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