在Windows批处理脚本的for循环中获取子字符串

Question

I'm not sure what I'm doing wrong here, but I'm trying to parse through some XML files in my folder and get a substring of the each file name. Here's what I got in my .bat file:

for %%f in (*.xml) do (
    echo %%f
    echo %%f:~3,-4%%
)

The first echo prints out the file name just fine. But the second echo is what I'm having trouble with. I'm getting outputs like, say, for NewABCDEFG.xml:

NewABCDEFG.xml
NewABCDEFG.xml:~3,-4%

When I should be getting:

NewABCDEFG.xml
ABCDEFG

I can't figure out what's wrong. If I run the substring command in command line by itself, it works fine. Any suggestions?

Answer 1

Fixed it with the following script:

setlocal EnableDelayedExpansion
for %%f in (*.xml) do (
set filename=%%f
echo !filename:~7,-4!
)

The set line was what I really needed to get this to work, to expand environment variables at execution time, per the help guide.

Answer 2

First change %%f to %%I , that will make it easier read.

for %%I in (*.xml) do echo %%I & echo %%~nI

No need for delayed expansion in this case. My preference however is to avoid having multi-command line blocks:

for %%I in (*.xml) do call :DoIt %%I
exit /b
:DoIt
echo %1
echo %~n1
exit /b 0

Also avoid the possible confusion between replacement variable and the modifiers, allowing you to use %%a .. %%z or %%A .. %%Z for instance.