vba while loop example
Example: vba while loop
i = 0
While i < 100
'Code here is executed 100 times.
i = i + 1
Wend
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'Notes: The While loop is terminated with the 'Wend' keyword.
'
' The While loop must include a Boolean expression directly after
' the 'While' keyword and the loop will execute for as long as the
' Boolean expression evaluates to True. This expression should be
' based on something that has the POTENTIAL TO CHANGE on each cycle
' through the loop. For example, 'i' in the above code.
'
' The While expression is evaluated at the beginning EACH cycle through
' the loop. The expression DOES NOT NEED to be NUMERIC; but it must
' evaluate to True or False. The While loop will be skipped entirely if
' the expression evaluates to False before the loop begins.
' The following code demonstrates how the above While loop
' functions (without actually using the 'While' and 'When' keywords):
i = 0
LoopStart:
If (i < 100) = False Then GoTo LoopEnd
'Code here is executed 100 times.
i = i + 1
GoTo LoopStart
LoopEnd:
' This is for demonstration purposes only. Although these two loops are
' equivalent, using the 'GoTo' statement should be avoided. The While loop
' accomplishes the exact same task, but cleanly, without the
' line labels and without the 'GoTo' statements.
'
'Note: VBA does not include an 'Exit While' statement to terminate the loop
' early. VBA does include the 'Exit Do' statement for the Do loop and
' also the 'Exit For' statement for the For loop. But it is possible
' to exit the While loop early with a 'GoTo' statement, but again, the
' 'GoTo' statement should be avoided. It's also possible to exit
' the While loop with the 'Exit Sub' and 'Exit Function' statements.
' But of course, these last two statements will not only exit the
' While loop, they will also immediately exit the current procedure.
'
'Note: From an efficiency standpoint, the For loop may be a better choice
' than the While loop because the For loop's range is calculated only
' once, before the For loop starts. By contrast, the While loop's
' expression is evaluated before each and every cycle of the loop.
'
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