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format an environment variable in DOS (Windows)

I write a DOS "script" (.cmd) where I want to recuperate the content of an environment variable containing a small number and format it in 3 digits (left padding with 0)
So if for example the environment variable is Number and contains 3, I want to have later on in another variable, says Formatted, a string 003
How can I do this in a cmd ?

Steve Knight

The easiest way is to add 1000 or a big enough number to it to fill in any missing 0's and then take the right n characters. You can do that as:
@echo off
set /p varA=Enter number:
set /a varA=varA +1000
set varA=%varA:~-3%
echo varA is now %varA%

You can do various changes to strings using the %variable:~x,x% and %variable:x=y% syntaxes which you can see more info in set /? from a cmd.exe prompt

Steve

Steve Knight

i.e. varA = 6, it then becomes 1006 and then 006.
if varA=1291 then it becomes 2291 and then 291
Steve

LeTay

ASKER

Excellent
I just forgot to mention the following
The script has as input argument the name of the output variable to set to
so ?

LeTay

ASKER

Says that the final script name is Pad.cmd
I call Pad as follows
Pad 12 MyVar
and at exit, the variable MyVar should contain 012
How do you handle this ? %1 inside contains 12 and %2 contains MyVar ?
Thanks

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Steve Knight

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Steve Knight

You can't use %%2:~-3% so did all the changes to tempvar then assigned tempvar into your variable name.

You should add I suppose

set tempvar=

just before the exit /b to remove the temp var too.