Cmd : not evaluating variables inside a loop

Question

trying to make a .bat script, and need to get some strings working properly.

This is what I've got so far

@echo off
for /r %%i in (*.csv) do (
set str=%%i
set str=%str:csv=rar%
echo %%i
echo.%str%
)

Say I've got this running in C:\, and got 5 csv, 1.csv, 2.csv... 5.csv

First time I run it, I get output of:

C:\1.csv

C:\2.csv

C:\3.csv

C:\4.csv

C:\5.csv

The second time I get:

C:\1.csv
csv=rar
C:\2.csv
csv=rar
C:\3.csv
csv=rar
C:\4.csv
csv=rar
C:\5.csv

Then all subsequent calls I get:

C:\1.csv
rar=rar
C:\2.csv
rar=rar
C:\3.csv
rar=rar
C:\4.csv
rar=rar
C:\5.csv

When what I would be expecting to get is straight through:

C:\1.csv
C:\1.rar
C:\2.csv
C:\2.rar
C:\3.csv
C:\3.rar
C:\4.csv
C:\4.rar
C:\5.csv
C:\5.rar

So I remove the substitution:

@echo off
for /r %%i in (*.csv) do (
echo %%i
set str=%%i
echo.%str%
)

First run:

C:\1.csv

C:\2.csv

C:\3.csv

C:\4.csv

C:\5.csv

Second Run:

C:\1.csv
C:\5.csv
C:\2.csv
C:\5.csv
C:\3.csv
C:\5.csv
C:\4.csv
C:\5.csv
C:\5.csv
C:\5.csv

It's like it's not set the str variable until the last run of the loop, even though it's trying to echo out the variable, the line of which occurs after the setting, and then saved this for the next loop? Is there something I'm missing on the way it processess loops?

Thanks

Answer 1

You should use setlocal enabledelayedexpansion. Actually, the content of %str:csv=rar% is evaluated only once before the loop runs. So:

@echo off
setlocal enabledelayedexpansion
for /r %%I in (*.csv) do (
set str=%%i
set str=!str:csv=rar!
echo %%i
echo.!str!
)
endlocal