Redim vba excel это

This tutorial will demonstrate how to use dynamic arrays (redim and redim preserve) in VBA.

Dynamic Array

Dynamic Arrays are arrays that can change sizes (as opposed to static arrays, which are static).

To declare a dynamic array, you declare the array, but omit the array size:

Dim strNames() As String

Then, before you can assign values to your array, you must use the ReDim Statement to set the array to your desired size:

ReDim strNames(1 to 3)

Now, anytime you want to change your array size, simply use ReDim (or ReDim Preserve as we’ll learn about below).

Dynamic Variant Arrays

Note: Variant Arrays are a little different. With variant arrays, you don’t need to set the array size with ReDim before assigning values.

Sub TestArray()
'declare the variable
    Dim varNames() As Variant
'populate the array
    varNames() = Array("Fred", "Wilma", "Barney", "Betty")
'return the values
    MsgBox Join(varNames, ",")
End Sub

Redim vs. Redim Preserve

The ReDim statement resizes an array, clearing all existing values.

The ReDim Preserve statement resizes an array, keeping (“preserving”) all existing values.

Using ReDim

In practice, resizing an array with ReDim looks like this:

Sub TestReDim()
'declare the string array
   Dim strNames() As String
'resize the string array to be able to hold 3 values
   ReDim strNames(1 to 3)
'populate the array with 3 names
   strNames(1) = "Mel"
   strNames(2) = "Steve"
   strNames(3) = "Bob"
'show the result in the immediate window
   Debug.Print Join(strNames, vbCrLf)
End Sub

Using ReDim Preserve

In this example, we will use ReDim to set the initial dynamic array and then ReDim Preserve to resize the array, keeping the original values:

Sub TestReDim()
'declare the string array
   Dim strNames() As String
'resize the string array to be able to hold 3 values
   ReDim strNames(1 to 3)
'populate the array
   strNames(1) = "Mel"
   strNames(2) = "Steve"
   strNames(3) = "Bob"
'show the result in the immediate window
   Debug.Print Join(strNames, vbCrLf)
'redim but preseve the data
   ReDim Preserve strNames(1 to 4)
   strNames(4) = "Fred"
'show the result in the immediate window
   Debug.Print Join(strNames, vbCrLf)
End Sub

If you do not use the PRESERVE statement, you would lose the data that had been in the array previously.

In the  immediate window above, the array populated Mel, Steve and Bob.  When it was re-declared, it remove those values and instead returned 3 blank values and then the value ‘Fred’.   This is due to the PRESERVE statement being omitted.

Excel VBA ReDim Statement

The VBA ReDim statement is similar to the Dim statement. But, the difference is that one may use it to store or allocate more storage space or decrease the storage space a variable or an array has. Now, there are two important aspects used with the statement: Preserve. If one uses Preserve with this statement, it creates a new array with different sizes. But, on the other hand, if one does not use Preserve with this statement, it just changes the array size of the current variable.

Arrays are an important part of VBA coding. Using arrays, we can store more than one value in the same variable we defined. Like how we declare the variable using the word “Dim,” we need to declare the array name by using “Dim” as well.

To declare the array name, we need first to identify the kind of array we are going to define. In arrays, we have 5 types:

1. Static Array
2. Dynamic Array
3. One Dimensional Array
4. Two Dimensional Array
5. Multi-Dimensional Array

In the static array in excelArray formulas are extremely helpful and powerful formulas that are used in Excel to execute some of the most complex calculations. There are two types of array formulas: one that returns a single result and the other that returns multiple results.read more, we will decide the lower value and upper value of the array well in advance while declaring the variable. For example, look at the below example.

Code:

Sub ReDim_Example1()
  
  Dim MyArray(1 To 5) As String

End Sub

MyArray is the array’s name, which can hold the value from 1 to 5. So, for example, MyArray can hold 5 different results, like the one below.

Code:

Sub ReDim_Example1()
  Dim MyArray(1 To 5) As String

  MyArray(1) = "Hi"
  MyArray(2) = "Good"
  MyArray(3) = "Morning"
  MyArray(4) = "Have a"
  MyArray(5) = "Nice Day"

End Sub

Dynamic Array with ReDim Statement

But in the dynamic array, this is not the case. Therefore, we will not decide on the lower and upper values well in advance. Rather, we define the array name and assign data type.

Sub ReDim_Example1()

Dim MyArray() As String

End Sub

To make the array name dynamic, we need to declare it with the word “Dim” first, but don’t decide the array size well in advance. Instead, we name an array with empty values inside the parenthesis (). When the array does not include size, it treats it as a dynamic array.

Dim MyArray() As String

When you mention the array size inside the parenthesis, it becomes a static array. Dim MyArray(1 to 5) As String.

In the dynamic array, we always resize the array size by using the word “ReDim” in the next line of the code.

ReDim MyArray(1 to 6) As String

Any value stored to the array name in the previous steps, i.e., using the “Dim” statement, stands null, and the size we declared using “ReDim” becomes the new size of the array.

Examples to use VBA Redim Statement

You can download this VBA ReDim Excel Template here – VBA ReDim Excel Template

Example #1

Look at the example of using the “ReDim” statement practically. Then, follow the below steps to apply “ReDim.”

Step 1: Create a macro name first.

Step 2: Declare an array name as a string.

Code:

Sub ReDim_Example1()

  Dim MyArray() As String

End Sub

Step 3: Now, use “Redim” and assign the array size.

Code:

Sub ReDim_Example1()

  Dim MyArray() As String
  ReDim MyArray(1 To 3)

End Sub

Step 4: The array name “MyArray” can hold up to 3 values here. Assign the value to these 3 arrays like the below one.

Code:

Sub ReDim_Example1()

  Dim MyArray() As String
  ReDim MyArray(1 To 3)

  MyArray(1) = "Welcome"
  MyArray(2) = "to"
  MyArray(3) = "VBA"

End Sub

So, the first array is equal to the word “Welcome,” and the second is equal to the word “to.” Finally, the third array is equal to the word “VBA.”

Step 5: Now, store these array values in cells.

Code:

Sub ReDim_Example1()

  Dim MyArray() As String
  ReDim MyArray(1 To 3)

  MyArray(1) = "Welcome"
  MyArray(2) = "to"
  MyArray(3) = "VBA"

  Range("A1").Value = MyArray(1)
  Range("B1").Value = MyArray(2)
  Range("C1").Value = MyArray(3)

End Sub

Step 6: If you run this code, we should have these values in A1, B1, and C1 cells, respectively.

Example #2 – Resize the Array Size While Remembering the Old Values.

Once the array name is assigned values, we can resize it at any point in the procedure by using the word “ReDim Preserve.”

Assume you have already declared an array name and assigned values to those array names like the below one.

Now, you would like to increase the array length by 2, i.e., 5. In this case, we can use the word VBA “ReDim Preserve” to resize the array length and remember the old values.

Code:

Sub ReDim_Example2()
  
  Dim MyArray() As String
  ReDim MyArray(3)

  MyArray(1) = "Welcome"
  MyArray(2) = "to"
  MyArray(3) = "VBA"

  ReDim Preserve MyArray(4)
  MyArray(4) = "Character 1"

  Range("A1").Value = MyArray(1)
  Range("B1").Value = MyArray(2)
  Range("C1").Value = MyArray(3)
  Range("D1").Value = MyArray(4)

End Sub

Now, we can assign two more values to the array.

Code:

Sub ReDim_Example2()

  Dim MyArray() As String
  ReDim MyArray(3)

  MyArray(1) = "Welcome"
  MyArray(2) = "to"
  MyArray(3) = "VBA"

  ReDim Preserve MyArray(4)
  MyArray(4) = "Character 1"

  Range("A1").Value = MyArray(1)
  Range("B1").Value = MyArray(2)
  Range("C1").Value = MyArray(3)
  Range("D1").Value = MyArray(4)

End Sub

Now, store these values in cells.

Code:

Sub ReDim_Example2()

  Dim MyArray() As String
  ReDim MyArray(3)

  MyArray(1) = "Welcome"
  MyArray(2) = "to"
  MyArray(3) = "VBA"

  ReDim Preserve MyArray(4)
  MyArray(4) = "Character 1"

  Range("A1").Value = MyArray(1)
  Range("B1").Value = MyArray(2)
  Range("C1").Value = MyArray(3)
  Range("D1").Value = MyArray(4)

End Sub

Now, run the Macro and see what happens.

So, we got the new word in the D1 cell.

We need to use the word “Preserve” because the array should remember the old array values in the procedure.

When you ignore the word “Preserve,” it will not remember old values.

Things to Remember Here

• The ReDim can only hold the last value of the array, not the many values. So, for example, we cannot use the code “ReDim Preserve MyArray(4 to 5)”. Instead, it will throw an error.
• We cannot ReDim static arrays. When you assign the array size inside the parenthesis, it becomes a static array.
• Using ReDim, we cannot change the data type. The array can hold whatever data type we have assigned while declaring the array.

Recommended Articles

This article has been a guide to VBA ReDim. Here, we discuss handling dynamic arrays using ReDim Preserve, examples, and a downloadable Excel template. Below are some useful Excel articles related to VBA: –

• VBA ISNULL
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Excel VBA ReDim

We can adjust the number of elements in an array through VBA Redim. Redim is not a function, it is Dynamic memory allocation program through Redim statement. When we do use Redim, a specific amount of memory is kept aside to store the data.

How to Use VBA ReDim Statement?

We will discuss how to use VBA ReDim Statement by using some examples.

You can download this VBA ReDim Excel Template here – VBA ReDim Excel Template

VBA ReDim – Example #1

When we use Dim for an array, we cannot change the value of data store in an array. But when we use Redim, we can change the stored value in an array. This process of changing the array is called re-dimensioning the array.

Suppose we have an array A of 4 cell value then it will be defined with;

• Dim A(3) As Double

As we can see all the cells has “0” as stored value. Now suppose if we Redim the Dim A with 3 cell data and store the value in it then it will look like as below.

• ReDim B(2) As Double

B(0) = 1; B(1) = 3, B(2) = -6

It will look like as;

Now if we want to add cells in it, we can do it. Then it will automatically assign the “0” to that cells. Now for implementing ReDim, press Alt + F11 to open VBA Window. And from the Insert menu select Module option to open a new window as shown below.

Now open Subcategory and add any name. As we are using ReDim so we have named as UsingReDim.

Code:

Sub UsingReDim()

End Sub

Now before defining ReDim, first define any Integer. Here we have defined it as “A” with array length 3. And store some values in a created array of 3 cells as shown below.

Code:

Sub UsingReDim()

Dim A(2) As Integer

ReDim A(2)

A(0) = 1
A(1) = 2
A(2) = 3

End Sub

Now printing the values stored in Integer A we need to create message box with the help of command MsgBox as shown below.

Code:

Sub UsingReDim()

Dim A(2) As Integer 

A(0) = 1
A(1) = 2
A(2) = 3

MsgBox A(0)
MsgBox A(1)
MsgBox A(2)

End Sub

Now run the code by clicking on the play button or F5 key as shown below.

Now we will use ReDim and it will store more than defined characters in the array. For this use ReDim for defined Integer A. Firstly, we will remove the defined cell count from Dim. The use of Redim function is as follows:

• ReDim A(2) is used for A(0), A(1), A(2) cells array.
• ReDim A(4) is used for A(0), A(1), A(2), A(3), A(4) cells with two extra dummy cells.

Code:

Sub UsingReDim()

Dim A() As Integer 

ReDim A(2)

A(0) = 1
A(1) = 2
A(2) = 3

ReDim A(4)

MsgBox A(0)
MsgBox A(1)
MsgBox A(2)

End Sub

Once done then run the complete code by clicking on the play button or using F5 key. Once we run the complete code, we will 3 message boxes but with a message containing only “0” as shown below.

Which is because ReDim actually has only 3 values but it did not carry stored values under defined integers. Using Redim only does not store any values and carry forward the previously stored values into it. To apply the same we need to preserve the values of defined integer A, with the help of ReDim. By using Preserve in VBA, we can store the value in ReDim. For this, we will add Preserve after ReDim in VBA Codeas shown below.

Code:

Sub UsingReDim()

Dim A() As Integer 

ReDim A(2)

A(0) = 1
A(1) = 2
A(2) = 3

ReDim Preserve A(4)

MsgBox A(0)
MsgBox A(1)
MsgBox A(2)

End Sub

Now run the complete code again. We will see 3 message boxes with all the stored values in it as show below. 

Now, you must be wondering why we used A(4) with ReDim Preserve?

Below is the explanation of it. Where 1^st, 2^nd and 3^rd position of array is occupied with values 1, 2 and 3 respectively. And 4^th and 5^th position which represents 3 and 4 count of array A are dummy cells. Which means, if there is not data stored 4^th and 5^th position then it will automatically consider the value “0” and message will not get populated.

If we try to see the values stored in 4^th and 5^th position of ReDim array, then we need to insert a message box for these 2 positions as well.

Code:

Sub UsingReDim()

Dim A() As Integer

ReDim A(3)

A(0) = 1
A(1) = 2
A(2) = 3

ReDim Preserve A(4)

MsgBox A(0)
MsgBox A(1)
MsgBox A(2)
MsgBox A(3)
MsgBox A(4)

End Sub

As we have added message boxed for 4^th and 5^th position without storing any value. Now run the code again.

As we can see in the above screenshots, for a 4^th and 5^th position we got message boxes but the value is showing as”0”. Which means explains the above statement. If there is no value defined then ReDim Preserve will automatically consider and fill “0” in the rest of the cells.

VBA ReDim – Example #2

Now let’s see how to use ReDim Statement with String instead of Integer.

Code:

Sub UsingReDim()

Dim A() As String 

ReDim A(3)

A(0) = "Customer"
A(1) = "Product"
A(2) = "Product Id"

ReDim Preserve A(4)

MsgBox A(0)
MsgBox A(1)
MsgBox A(2)
MsgBox A(3)
MsgBox A(4)

End Sub

Once done, then run the complete code using F5 key or manually as shown below. 

As we can see in the above screenshot we are getting all the defined and stored characters in first 3 message boxes. And in 4^th and 5^th box we are getting nothing. As ReDim stores no value if not defined. For Integers it will reflect as “0” but with String, it will show only blank messages.

Pros Of Excel VBA ReDim

• VBA ReDim allows us to redefine the dimension values.
• We can define as many as dimensional arrays with no or zero value and store the values later.
• ReDim meaning Re-Dimensioning gives use the allowances of adding any numbers of data arrays without increasing the size of stored data.

Things To Remember

• Always remember to add Preserve after ReDim in VBA, so that it will store the previously used dimensions.
• If a dimension is defined as String, then any position left blank in assigning values, will carry blank and once we print the same with the help of message box will give blank message box as well.
• If we have defined the dimensions Dim with 3 characters or cell values, then in ReDim we can use any number of dimensions carrying already defined and stored values in Dim.

Recommended Articles

This has been a guide to Excel VBA ReDim. Here we discussed how to use VBA ReDim Statement to remove spaces along with some practical examples and downloadable excel template. You can also go through our other suggested articles–

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3. VBA Find
4. VBA TRIM