String processing in windows batch files: How to pad value with leading zeros?

Question

in a Windows cmd batch file (.bat), how do i pad a numeric value, so that a given value in the range 0..99 gets transformed to a string in the range \"00\" to \"99\". I.e. I

Answer 1

If you are confident that the number of digits in your original number is always <= 2, then

set "x=0%x%"
set "x=%x:~-2%"

If the number may exceed 2 digits, and you want to pad to 2 digits, but not truncate values larger then 99, then

setlocal enableDelayedExpansion
if "%x%" equ "%x:~-2%" (
  set "x=0%x%"
  set "x=!x:~-2!"
)

Or without delayed expansion, using an intermediate variable

set paddedX=0%x%
if "%x%" equ "%x:~-2%" set "x=%paddedX:~-2%"

The nice thing about the above algorithms is it is trivial to extend the padding to any arbitrary width. For example, to pad to width 10, simply prepend with 9 zeros and preserve the last 10 characters

set "x=000000000%x%"
set "x=%x:~-10%"

TO prevent truncating

set paddedX=000000000%x%
if "%x%" equ "%x:~-10%" set "x=%paddedX:~-10%"