Using "for" command in a batch file

[Chris]

I'm not sure if this is the right newsgroup -- please let me know if
there is a better one.

I'm trying to construct an environment variable that contains a list of
all the files in a directory. Something like this:

for %%f in (mydir\*.txt) DO set mylist=%mylist%;%%f

This should be equivalent to "set mylist=;file1.txt;file2.txt;file3.txt"

Instead I get "mylist=;file3.txt"

It doesn't seem to be updating the mylist variable on each loop.
Instead, it just saves the value on the last loop.

What am I doing wrong?

 

[Pegasus \(MVP\)]

I'm not sure if this is the right newsgroup -- please let me know if
there is a better one.

I'm trying to construct an environment variable that contains a list of
all the files in a directory. Something like this:

for %%f in (mydir\*.txt) DO set mylist=%mylist%;%%f

This should be equivalent to "set mylist=;file1.txt;file2.txt;file3.txt"

Instead I get "mylist=;file3.txt"

It doesn't seem to be updating the mylist variable on each loop.
Instead, it just saves the value on the last loop.

What am I doing wrong?

By default each line of a batch file is scanned once to resolve
its environmental variables. You need to scan in each time
you run through the loop. Try the following version:
@echo off
setlocal enabledelayedexpansion
set MyList=
set Separator=
for %%a in (*.txt) do (
set MyList=!MyList!!Separator!%%a
set Separator=,
)
echo %MyList%
endlocal

Run for /? from a Command Prompt to get the documentation
on this technique

 

[Anon E. Mouse]

By default each line of a batch file is scanned once to resolve
its environmental variables. You need to scan in each time
you run through the loop. Try the following version:
@echo off
setlocal enabledelayedexpansion
set MyList=
set Separator=
for %%a in (*.txt) do (
set MyList=!MyList!!Separator!%%a
set Separator=,
)
echo %MyList%
endlocal

Run for /? from a Command Prompt to get the documentation
on this technique

Thanks. That worked perfectly.