Batch list all file extension in a specific directory-CodePudding

Using windows batch file, I am trying to echo a list of file extensions in a folder. That will then be set as %var% and output to .txt file

@setlocal & @(for %%I in (*.*) do @set /a ext[%%~xI]  = 1) & set ext[

from this post Windows command to get list of file extensions

My end game is I would like it to output like so

folder contents:

sample1.jpg
sample2.jpg
sample3.jpg
sample4.mp4
sample5.mp4
sample6.png
sample7.zip
sample8.zip

result:

.jpg, .mp4, .png, .zip

Any help is greatly appreciated, I hope I explained it clear enough

CodePudding user response：

You already have defined a variable for each extension. Just use another for /f loop to concatenate the relevant part (the actual extension) of them:

@echo off
setlocal enabledelayedexpansion

for %%I in (*) do @set /a ext[%%~xI]  = 1 
for /f "tokens=2 delims=[]" %%a in ('set ext[') do set "var=%%a, !var!"
echo %var:~0,-2%

CodePudding user response：

@setlocal ENABLEDELAYEDEXPANSION&@(for %%I in (*.*) do @set /a ext[%%~xI]  = 1&IF DEFINED ext[all]  (IF "!ext[all]!" equ "!ext[all]: %%~xI=!" SET "ext[all]=!ext[all]!, %%~xI") ELSE (SET "ext[all]= %%~xI"))&SET "ext[all]=!ext[all]:~1!"&set ext[

Why you want this all on one line, I've no idea.

Since you need to access the changed value of a variable within a loop, you need delayedexpansion. Note that Space.ext is appended each time a new extension is found, so there will be an extra space at the start of the list variable - hence the requirement to remove the first character before displaying the result.