Why variables set in for loops do not exist - batch-file

Question

I write two for loops to do data automation. While variables echoed well in each loop, the last step (data process using a well-written batch) keeps giving errors that variables set previous do not exist.
The code loops through the subfolders (q1, q2, etc.) under the directory. For each subfolder, there is another for loop to set several variables. I echoed three variables fine in loops.
However, when using a batch called abc.rb, the error is COM_M does not exist.
Actually, the error is all three variables do not exist.
setlocal ENABLEDELAYEDEXPANSION
for /f %%f in ('dir /ad /b ') do (
echo %%f
pause
pushd %%f
for %%a in (*.a*.dat) do (
set COM_DATA=%%a
echo !COM_DATA!
set COM_V=%%f\com-v.dat
echo !COM_V!
set COM_M=%%f\com-M.dat
echo !COM_M!
)
chdir
set fig=someA
set matrix=someB
rem use a written batch (called abc.rb) to process data
abc.rb -a !COM_DATA! -b !COM_V! -c !COM_M! -d !fig! -e !matrix!
popd
)
endlocal
Can anyone find any bugs? Thank you!

Answer 1

I am not sure why the need to pushd into the dir, but as far as I can see, there is only a need for a single for loop:
#echo off
setlocal enabledelayedexpansion
set "fig=someA"
set "matrix=someB"
for /R %%a in (*.a*.dat) do (
set "COM_DATA=%%a"
echo !COM_DATA!
set "COM_V=%%~dpacom-v.dat
echo !COM_V!
set COM_M=%%~dpacom-M.dat
echo !COM_M!
rem If abc.rb is is NOT a windows batch file, remove call below
call abc.rb -a "!COM_DATA!" -b "!COM_V!" -c "!COM_M!" -d !fig! -e !matrix!
)
If you require the pushd (which I doubt)
#echo off
setlocal enabledelayedexpansion
set "fig=someA"
set "matrix=someB"
for /R %%a in (*.a*.dat) do (
pushd "%%~dpa"
set "COM_DATA=%%a"
echo !COM_DATA!
set "COM_V=%%~dpacom-v.dat"
echo !COM_V!
set "COM_M=%%~dpacom-M.dat"
echo !COM_M!
rem If abc.rb is is NOT a windows batch file, remove call below
call abc.rb -a "!COM_DATA!" -b "!COM_V!" -c "!COM_M!" -d !fig! -e !matrix!
popd
)
The double quotes will help if the paths have whitespace, if your program has an issue with them, then you can remove them: abc.rb -a !COM_DATA! -b !COM_V! -c !COM_M! -d !fig! -e !matrix!

Answer 2

#echo off
setlocal ENABLEDELAYEDEXPANSION
set "fig=someA"
set "matrix=someB"
set "COM_V=com-v.dat"
set "COM_M=com-M.dat"
for /f %%f in ('dir /ad /b') do (
echo %%f
pause
if exist "%%~f\*.a*.dat" (
pushd "%%~f" && (
for %%a in (*.a*.dat) do (
set "COM_DATA=%%~a"
echo !COM_DATA!
)
chdir
rem use a written batch called abc.rb to process data
call abc.rb -a "!COM_DATA!" -b "!COM_V!" -c "!COM_M!" -d "!fig!" -e "!matrix!"
popd
)
)
)
endlocal
Issues:
If the nested for loop finds no files with the matched pattern of *.a*.dat, then the variables COM_DATA, COM_V and COM_M may not be defined or updated with a newer value.
Value of COM_DATA is a filename. Values of COM_V and COM_M is the parent folder name and filename, which is inconsistent. Based on the current directory, I would consider filenames as correct. This means that COM_V and COM_M never need to change.
If abc.rb is a batch-file, then you need to use call for the interpreter to return control back to the main script.
Changes:
Test if the file pattern exists, and run the code within the code block if true.
COM_V and COM_M moved out of the for loop as values never change.
Calling abc.rb as being a batch-file.
fig and matrix moved out of the for loop as values never change.
Double quote setting of variables and use of variables to avoid issues with spaces, special characters etc.
pushd && ( ensures the code within the parentheses is run only on success of changing directory.
Removed parentheses in the rem line. They may not cause a problem, though rem lines are parsed and can cause a syntax error. Suggest avoiding special characters in rem lines unless you intend to debug.