https://en.wikibooks.org/wiki/Windows_Batch_Scripting

from http://stackoverflow.com/questions/11235153/how-to-find-if-a-string-is-in-a-list-of-strings-in-a-dos-batch-file

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]!"