Capitalize first letters word

Just because this sort of thing is fun for me, here are two more solutions.

Split into words, initial-cap each word from the split groups, and rejoin. This will change the white space separating the words into a single white space, no matter what it was.

s = 'the brown fox'
lst = [word[0].upper() + word[1:] for word in s.split()]
s = " ".join(lst)

EDIT: I don’t remember what I was thinking back when I wrote the above code, but there is no need to build an explicit list; we can use a generator expression to do it in lazy fashion. So here is a better solution:

s = 'the brown fox'
s = ' '.join(word[0].upper() + word[1:] for word in s.split())

Use a regular expression to match the beginning of the string, or white space separating words, plus a single non-whitespace character; use parentheses to mark «match groups». Write a function that takes a match object, and returns the white space match group unchanged and the non-whitespace character match group in upper case. Then use re.sub() to replace the patterns. This one does not have the punctuation problems of the first solution, nor does it redo the white space like my first solution. This one produces the best result.

import re
s = 'the brown fox'

def repl_func(m):
    """process regular expression match groups for word upper-casing problem"""
    return m.group(1) + m.group(2).upper()

s = re.sub("(^|s)(S)", repl_func, s)


>>> re.sub("(^|s)(S)", repl_func, s)
"They're Bill's Friends From The UK"

I’m glad I researched this answer. I had no idea that re.sub() could take a function! You can do nontrivial processing inside re.sub() to produce the final result!

Strings are one of the most used python data structures. While programming in python, some strings are used in uppercase while some are in lowercase and some in combination. Hence, it is chaotic to pay attention to every string you create and use while programming, and also quite difficult to correct it manually.

As it is important and default format to capitalize the first letter of every word for readers convenience, we have presented a detailed article representing 8 different methods to capitalize the first letter in python and the examples. But, before learning those methods, let us have a brief introduction to strings in python.

What are Strings in Python?

Python string is the collection of the characters surrounded by single quotes, double quotes, or triple quotes. The computer does not understand the characters; internally, it stores manipulated characters as the combination of the 0’s and 1’s. This means that strings can be parsed into individual characters and that individual characters can be manipulated in various ways.

This is what makes Python so versatile: you can do almost anything with it, and some things even work the way they do in another language. To learn more about strings in python, refer to our article «4 Ways to Convert List to String in Python».

For Example

Output

How to Capitalize the First Letter in Python?

Below are the eight methods to capitalize the first letter of strings in python:

1) Using str.capitalize() to capitalize first letter

The string.capitalize () function takes the string argument and returns the first letter of the capitalized word. This can be useful if you have a lot of text that you want to format as uppercase automatically or if you want to change the file’s name or folder. The function works on any string containing English letters, numbers, and punctuation marks.

For Example

s = "python"
print("Original string:")
print(s)
print("After capitalizing first letter:")
print(s.capitalize())

Output

Original string:
python
After capitalizing first letter:
Python

2) Using string slicing() and upper() method

We used the slicing technique to extract the string’s first letter in this method. We then used the upper() method of string manipulation to convert it into uppercase. This allows you to access the first letter of every word in the string, including the spaces between words. The below example shows the working of this method in detail.

For Example

s = "python"
print("Original string:")
print(s) 
result = s[0].upper() + s[1:]
print("After capitalizing first letter:")
print(result)

Output

Original string:
python
After capitalizing first letter:
Python

3) Using str.title() method

string.title() method is a very simple and straightforward method of generating titles for strings. As the titles for string have a default structure where the first letter is always in upper case, this method helps us capitalize the first letter of every word and change the others to lowercase, thus giving the desired output. This method is also useful for formatting strings in HTML and formatting strings in JavaScript and other programming languages.

For Example

s = "python"
print("Original string:")
print(s)
print("After capitalizing first letter:")
print(str.title(s))

Output

Original string:
python
After capitalizing first letter:
Python

When we use the entire sentence as the input string, it will capitalize the first letter of every word in the string, as shown below.

For Example

s = "it's DIFFICULT to identify 10a "
# Capitalize the first letter of each word
result = s.title()
print(result)

Output

It isn't easy To Identify 10A

The behaviors drawn from the above example are:

1. “DIFFICULT” is converted into “Difficult” because the title function only capitalizes the first letter of every word and keeps the remaining characters of the word as lower case.
2. “it’s” is converted to «It’S” because the function considers “it’s” as two separate words by considering apostrophes.
3. “10a” is converted to “10A” because the title function considers “as the first character for the word “a.»

4) Using capitalize() function to capitalize the first letter of each word in a string

Here, we make use of the split() method to split the given string into words. The generator expression iterates through the words, using the capitalize() method to convert the first letter of each word into uppercase. The capitalize() method converts each word’s first letter to uppercase, giving the desired output. The below example shows the working of the capitalize function in detail.

Example

s = "python"
print("Original string:")
print(s)
print("After capitalizing first letter:")
result = ' '.join(elem.capitalize() for elem in s.split())
print(result)

Output

Original string:
python
After capitalizing first letter:
Python

5) Using string.capwords()

capwords() is a python function that converts the first letter of every word into uppercase and every other letter into lowercase. The function takes the string as the parameter value and then returns the string with the first letter capital as the desired output. Check out the below example to understand the working of the capwords() function.

For Example

import string
s = "python"
print("Original string:")
print(s)
print("After capitalizing first letter:")
result = string.capwords(s)
print(result)

Output

Original string:
python
After capitalizing first letter:
Python

6) Using regex to capitalize the first letter in python

Regex is generally known as a regular expression in python, is a special sequence of characters that helps match or find the other strings. Using regex, you can search the starting character of each word and capitalize it. For using this method, you have to import the regex library using the “import” keyword before defining the main function, as shown in the below example. Also, remember that this method only capitalizes the first character of each word in python and does not modify the whitespaces between the words.

For Example

import re
def convert_into_uppercase(a):
    return a.group(1) + a.group(2).upper()
s = "python is best programming language"
result = re.sub("(^|s)(S)", convert_into_uppercase, s)
print(result)

Output

Python Is Best Programming Language

7) Capitalize the first letter of every word in the list

You must wonder how difficult it would be if we had an entire list of words as a string instead of a single string to capitalize the first letter in python. Well, it is quite simple. When you have an entire list of words and wish to capitalize the first letter of every word, you can iterate through the words in the list using for loop and then use the title() method in python. This process will help you to convert the first letter of each word in the list to uppercase.

For Example

fruits=['apple','grapes','orange']
print('Original List:')
print(fruits)
fruits = [i.title() for i in fruits]
print('List after capitalizing each word:')
print(fruits)

Output

Original List:
['apple', 'grapes', 'orange']
List after capitalizing each word:
['Apple', 'Grapes', 'Orange']

Capitalize the first letter of each word in the file

Capitalizing the first letter of any given the word manually is quite feasible, but what if you have to capitalize the first letter of every word in any given file? Well, it is quite easy too. For this situation, you have to use the open() method to open the file in the reading mode and then iterate through every word using for loop. Later, you can capitalize the first letter of every word using the title() function, just like shown in the below example.

For Example

file = open('readme.txt', 'r') 
for line in file: 
    output = line.title() 
 
    print(output)

Output

Hello! Welcome To Favtutor

Conclusion

As strings are frequently used data structure while programming in python, it is not feasible to capitalize the first letter of each string word manually. Hence, we have presented various ways to convert the first letter in the string as uppercase. All these functions draw the same output, and hence you can choose the one according to your need. However, if you face any difficulty, get in touch with our python tutors to solve your doubts.

Python has many built-in methods that perform operations on strings. One of the operations is to change the case of letters. We’ll see different ways to change the case of the letters in a string, and go through many examples in each section, and finally go through some of the applications.

Python strings are immutable, which means that once created these strings cannot be modified. As a consequence, most of the functions that operate on strings actually return a modified copy of the string; the original string is unchanged.

Let’s take a look at some of the ways we can manipulate strings to change the case of words.

Different cases

We have covered different cases like:

• Capitalize the first letter using capitalize()
• Convert the entire string to upper-case
• Convert the entire string to lower-case
• Capitalize first letter of each word

Capitalize the first letter using capitalize()

To capitalize the first letter, use the capitalize() function. This functions converts the first character to uppercase and converts the remaining characters to lowercase. It doesn’t take any parameters and returns the copy of the modified string.

Syntax:
str s.capitalize()

Example:

s = "hello openGeNus"
t = s.capitalize()
print(t)

'Hello opengenus'

Notice that the function capitalize() returned a modified copy of the original string. This means that our original string s was not modified.
The first letter ‘h’ was converted to ‘H’. Further an upper-case letter ‘G’ was converted to its lower-case letter ‘g’ and similarly ‘N’ was converted to ‘n’

Convert the entire string to upper-case

To convert all the letters of the string to uppercase, we can use the upper() function. The function does not take any parameters and returns the copy of modified string with all letters converted to upper-case.

Syntax:
str s.upper()

Example:

s = "hello openGeNus"
t = s.upper()
print(t)

'HELLO OPENGENUS'

Convert the entire string to lower-case

To convert all the letters of the string to lowercase, we can use the lower() function. This function does not take any parameters and converts all the letters to lowercase.

Syntax:
str s.lower()

Example:

s = "hello openGeNus"
t = s.lower()
print(t)

'hello opengenus'

Capitalize first letter of each word

To capitalize the first letter of each word use the title() function. This function does not take any parameters and converts the first letter of each word to uppercase and rest of the letters to lowercase and returns the modified copy of the string.

Syntax:
str s.title()

Example:

s = "hello openGeNus"
t = s.title()
print(t)

'Hello Opengenus'

Notice that while each word was capitalized, the rest of the letters were converted to lowercase.

Applications

Now that we know how to perform basic case-manipulation, lets see how can this be useful for us?
There are many simple applications, we’ll go through some of the basic ones.

Prompts

A prompt is a text message that prompts the user to enter some input. For example, a prompt to enter a number.

A simple prompt could be to allow user to provide a permission by typing the word ‘Yes’. In python «Yes», «yeS» or «YES» are all distinct strings, and we need to be able to accept all variants of those. We can write code to check each of those individually, but the lower() or upper() function provides an easy way.

Let’s go through some sample code

in = input("Type 'Yes' to continue or 'No' to abort: ")
if in.lower() == "yes":
    print("task continued")
    # ... more functions
else: 
    print("task aborted")
    # user did not type Yes

Here, we checked for input ‘Yes’ and every other input would be considered as a ‘No’. This is sometimes useful, but adding a check for ‘No’ might be required; especially when you want to provide additional messages when user types invalid inputs like a number, instead of ‘Yes’ or ‘No’.

Searching names

Usually, to speed up searching process, names are better stored in the same case. This is done only when the changing the case would not cause any problems. The reason why you’d want to do this could be to make searching faster. Searching for someone named Alice as «ALice», «ALICE» or «alice» could be confusing and lead to unnecessary work.

To overcome this problem, names could be stored in upper-case by using the upper() or in lowercase using the lower() function. This would allow for faster searches because now you don’t have to convert all the names while you perform searches which can be time consuming if there are many names or if the search is occurring multiple times. This is usually done in a students list of names, where case of the names would not matter.

E-mail addresses

E-mail addresses are not case-sensitive. So in an application that requires sign in, you have to be able to handle all types of email address inputs.

Email addresses like «example@example.com», «Example@example.com» or «EXAMPLE@example.com» are all same email addresses, but different python strings. Thus the input needs to be converted to lower-case, which is common format for email addresses.

Here, the lower() function would be useful.

uname = input("Enter your email id: ")
temp = uname.lower()
if search(temp):           # search() defined elsewhere
    passwd = input("Enter your password: ")
else:
    print("account not found")

here, we have assumed that there is a function search() that searches for temp and returns a boolean value depending on whether or not the email was found.

In JavaScript, there is a lot of different ways to capitalize the first letter of a string.

You can capitalize the first letter with a combination of built-in javascript functions, with regex expressions and, even with CSS.

Read this article to find out your favorite new way. 😎

How to capitalize the first letter in JavaScript?

1. Using the charAt() with the slice() function

To capitalize the first letter of a string you need to follow these steps:

1. Get the first character with the charAt() function
2. Uppercase it with the toUpperCase() function.
3. Concatenate the rest of the string to the uppercased character.

javascriptconst str = "this is a very long string!";

// This will return: "This is a very long string!"
console.log(str.charAt(0).toUpperCase() + str.slice(1));

Read more: The slice function

2. Using the replace() function

You can also capitalize the first letter of a string by using the replace() function and a regex.

1. You create a regex that will only match the first character (this is the regex: /./).
2. With the replace() function, you uppercase the first character by matching the regex.

typescriptconst str = "this is a very long string!";

// This will return: "This is a very long string!"
console.log(str.replace(/./, c => c.toUpperCase()));

3. Using CSS

You can also capitalize the first letter using the CSS text-transform property and the ::first-letter selector.

xml<div id="my_title">this is a very long string!</div>
<style>
    #my_title::first-letter {
        text-transform: capitalize;
    }
</style>

4. Using Lodash

Alternatively, you can use lodash to do this for you.

Lodash has a special capitalize() function.

javascriptconst str = "this is a very long string!";

_.capitalize(str);

How to capitalize the first letter of each word?

1. Using a regex

To capitalize the first letter of each word you can use the replace() function with a regex.

typescriptconst str = 'this is a very long string!';

// This will return: "This Is A Very Long String!"
console.log(str.replace(/(^w|sw)/g, m => m.toUpperCase()));

Here is a table explaining this regex:

The g modifier means global. It means that the regex will find all matches.

2. Using the map() function

Also, you can capitalize the first letter of each word by following these steps:

1. Make all the text lowercase.
2. Split all the words inside an array.
3. Iterate through each word inside the array using the map() function and uppercase the first letter.
4. Transform the array into a string using the join() function.

typescriptlet str = 'this is a very long string!';

str = str.toLowerCase()
    .split(' ')
    .map((s) => s.charAt(0).toUpperCase() + s.substring(1))
    .join(' ');

// This will return: "This Is A Very Long String!"
console.log(str);

3. Using a for loop

You can also capitalize the first letter of each word by looping through each word with a for loop using the length property.

javascriptconst words = 'this is a very long string!'.split(" ");

for (let i = 0; i < words.length; i++) {
    words[i] = words[i][0].toUpperCase() + words[i].substr(1);
}

const str = words.join(' ');

// This will return: "This Is A Very Long String!"
console.log(str);

4. Using CSS

If you don’t want to use JavaScript, we have good news for you!

You can use the CSS text-transform property to archive the same result.

xml<div id="my_title">this is a very long string!</div>
<style>
    #my_title {
        text-transform: capitalize;
    }
</style>

How to capitalize all the letters in a word?

To capitalize all the letters of a string you need to use the toUpperCase() built-in function. You learn more by reading the article that I have written about the toUpperCase function.

Final Thoughts

As you can see, there is a lot of different ways to choose from when you want to capitalize the first letter of a string.

In my case, when I develop a new application, I create a helper function called capitalize(str: string) in my utils file and import it whenever I need to use it.

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