VBA For loop not exiting

Question

I am looping through rows of a table and deleting rows if certain conditions are not met. For some reason my for loop never exits even when its done. What am I doing wrong?<

Answer 1

You are subtracting 1 from the loop variable, so it loops forever.

In Visual Basic for loops, "from" and "to" are calculated once at the beginning (they are fixed), but the loop variable is increased each time. So

For r = fromExp to toExp
  SomeCode()
End For

       behaves the same as

    Dim f = fromExp
    Dim t = toExp

    r = f

    While (r < t)
       SomeCode()
       r = r + 1
    End While

In your example, the code changes toExp

For r = fromExp to toExp
   toExp = toExp + 1
   r = r - 1
EndFor

       but that doesn't affect the loop:

    Dim f = fromExp
    Dim t = toExp

    r = f

    While (r < t)
       toExp = toExp + 1   // does not affect the loop
       r = r - 1
       r = r + 1           // r is unchanged
    End While

The loop variable is unchanged, so it loops forever.

Best practice: do not alter the loop variable within a For loop.