Batch File : Read File Names from a Directory and Store in Array

Simulating Array

String is the only variable type in batch file. However, arrays can be simulated with several variables of identical name except a trailing numerical ID such as:

Array[1]    Array[2]    Array[3]    Array[4]     etc...

We can store each file name into these variables.

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Retrieving command output

The first step is to put the command output into a variable. We may use the for /f loop.

for /f %%G in ('dir *.txt /b') do set filename=%%~G

The ('') clause and /f option specifies to collect the command output. Note that the filename you get is always the last one displayed because of variable-overwriting. This can be resolved by appending instead, but is beyond the scope of this answer.

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Giving ID to files

In this case, I will name the array filename with a trailing ID [n], where n is a numerical ID.

setlocal enableDelayedExpansion
set /a ID=1

for /f "delims=" %%G in ('dir *.txt /b') do (
    set filename[!ID!]=%%~G
    set /a ID+=1
)

set filename
endlocal

Two things to note:

• I have added "delims=" into the loop to ensure it works properly with default delimiters.

• I replaced %ID% with !ID! because of delayed expansion. In short, when delayed expansion is disabled, the entire for loop is phrased before runtime, variables with new values are not updated block(()) structures; if enabled, the said variables are updated. !ID! indicates the need for update in each loop.

You can give a try for this batch file :

@echo off
Title Populate Array with filenames and show them
set "MasterFolder=%userprofile%\desktop"
Set LogFile=%~dpn0.txt
If exist "%LogFile%" Del "%LogFile%"
REM Iterates throw all text files on %MasterFolder% and its subfolders.
REM And Populate the array with existent files in this folder and its subfolders
echo     Please wait a while ... We populate the array with filesNames ...
SetLocal EnableDelayedexpansion
@FOR /f "delims=" %%f IN ('dir /b /s "%MasterFolder%\*.txt"') DO (
    set /a "idx+=1"
    set "FileName[!idx!]=%%~nxf"
    set "FilePath[!idx!]=%%~dpFf"
)

rem Display array elements
for /L %%i in (1,1,%idx%) do (
    echo [%%i] "!FileName[%%i]!"
    ( 
        echo( [%%i] "!FileName[%%i]!"
        echo Path : "!FilePath[%%i]!"
        echo ************************************
    )>> "%LogFile%"
)
ECHO(
ECHO Total text files(s) : !idx!
TimeOut /T 10 /nobreak>nul
Start "" "%LogFile%"