Learn about VBA Do Until Loop

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Learn about VBA Do Until Loop

In VBA (Visual Basic for Applications), the Do Until loop is used to repeat a block of code until a specified condition is True. Unlike the Do While loop, which runs while a condition is True, the Do Until loop keeps running as long as the condition is False and stops once the condition becomes True.

Syntax

The condition is checked before each iteration. If the condition is True at the start, the loop will not execute. You can also exit the loop prematurely using Exit Do.

Example 1: Do Until loop

Sub ExampleDoUntil()

Dim counter As Integer

counter = 1

Do Until counter > 5

MsgBox “Counter: ” & counter

counter = counter + 1

Loop

End Sub

In this example, the loop runs until counter is greater than 5. It increments counter by 1 in each iteration and stops when counter reaches 6.

Example 2: Do Until with a condition inside the loop

Sub ExampleDoUntilExit()

Dim i As Integer

i = 1

Do Until i = 5

If i = 3 Then

MsgBox “Exiting at i = 3”

Exit Do

End If

i = i + 1

Loop

End Sub

In this example, the loop stops when i equals 3, even though the condition is set to stop at 5.

Difference Between Do While and Do Until

  • Do While runs as long as the condition is True.
  • Do Until runs as long as the condition is False.

Example 3: Loop through a range of cells using Do Until

Sub LoopThroughCellsUntil()

Dim i As Integer

i = 1

 

Do Until Cells(i, 1).Value = “”

MsgBox Cells(i, 1).Value

i = i + 1

Loop

End Sub

This code loops through cells in column A, displaying the value of each cell until it finds a blank cell.

Q & A

  1. What is a Do Until loop in VBA?

Answer: A Do Until loop in VBA runs repeatedly until a specified condition is True. The loop executes the block of code while the condition is False. Once the condition becomes True, the loop terminates.

Example:

Sub ExampleDoUntil()

Dim i As Integer

i = 1

Do Until i > 5

MsgBox “Value of i: ” & i

i = i + 1

Loop

End Sub

This loop runs until i becomes greater than 5.

2. What is the difference between Do Until and Do While in VBA?

Answer: The main difference is how the condition is evaluated:

  • Do While loop: Executes as long as the condition is True.
  • Do Until loop: Executes as long as the condition is False.

Example of Do While:

Sub DoWhileExample()

Dim i As Integer

i = 1

Do While i <= 5

MsgBox “i is: ” & i

i = i + 1

Loop

End Sub

Example of Do Until:

Sub DoUntilExample()

Dim i As Integer

i = 1

Do Until i > 5

MsgBox “i is: ” & i

i = i + 1

Loop

End Sub

3. Can I use an Exit Do statement within a Do Until loop in VBA?

Answer: Yes, you can use the Exit Do statement to force the loop to stop even if the condition for the Do Until loop has not been met. This is useful if you want to break out of the loop early under certain conditions.

Example:

Sub ExitDoExample()

Dim i As Integer

i = 1

Do Until i > 10

If i = 5 Then

MsgBox “Exiting the loop at i = 5”

Exit Do

End If

i = i + 1

Loop

End Sub

4. How can I loop through a range of cells using a Do Until loop in VBA?

Answer: You can use a Do Until loop to iterate through a range of cells in Excel. This example shows how to loop through column A until an empty cell is encountered.

Sub LoopCellsUntilBlank()

Dim i As Integer

i = 1

 

Do Until Cells(i, 1).Value = “”

MsgBox Cells(i, 1).Value

i = i + 1

Loop

End Sub.

This loop checks each cell in column A and continues until it finds an empty cell.

5. Can I nest a Do Until loop inside another loop in VBA?

Answer: Yes, you can nest a Do Until loop inside another loop. This is useful for iterating over multiple dimensions, such as rows and columns in a range.

Example:

Sub NestedLoopExample()

Dim i As Integer, j As Integer

i = 1

Do Until i > 3

j = 1

Do Until j > 3

MsgBox “i: ” & i & ” j: ” & j

j = j + 1

Loop

i = i + 1

Loop

End Sub

This code will display message boxes showing combinations of i and j values.

 

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