How to find if a string is in a list of strings in a DOS batch file

Question

I'd like to check if an argument to a batch file is valid based on a list of strings.

For example:

IF %1 IN validArgument1, validArgument2, validArgument3 SET ARG=%1

This would set ARG to one of the valid arguments only if it matched. Ideally case insensitively.

Answer 1

You may also use the array approach:

setlocal EnableDelayedExpansion

set arg[1]=validArgument1
set arg[2]=validArgument2
set arg[3]=validArgument3

for /L %%i in (1,1,3) do if /I "%1" equ "!arg[%%i]!" SET "ARG=!arg[%%i]!"

In my opinion, this method is clearer and simpler to manage with multiple options. For example, you may create the array of valid arguments this way:

set i=0
for %%a in (validArgument1 validArgument2 validArgument3) do (
   set /A i+=1
   set arg[!i!]=%%a
)

---

Another possibility is to define a variable for each valid argument:

for %%a in (validArgument1 validArgument2 validArgument3) do set %%a=1

... and then just check the parameter this way:

if defined %1 (
   echo %1 is valid option...
   SET ARG=%1
)