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
- 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.
