rename a file removing part of the filename batch script - batch-file

Question

I have some files in the form:
filename1 1 extra1.ext
filename1 2.ext
filename1 3 extra2.ext
...
filename2 1.ext
filename2 100 extra3.ext
...
filename20 1.ext
filename20 15 extra100.ext
(etc.)
...where filename1, filename2, etc., can contain spaces, symbol ' but not numbers. And extra1, extra2, etc, can contain anything. The number in the file name enclosed by spaces does not repeat per same filename1, filename2, etc.
What i want is to remove the extra things of the files that contain it. That is, to get from filename20 15 extra100.ext to filename20 15.ext
My first attempt is this:
#echo off
setlocal EnableExtensions EnableDelayedExpansion
set "FILE=file name 11 con sosas extras 2.txt"
set "ext=txt"
set "folder=."
for /F "tokens=1,* delims=0123456789" %%A in ("!FILE!") do (set "EXTRA=%%B")
set "FIRST=!FILE:%EXTRA%=!"
set "filename=!FIRST!.!ext!"
echo !EXTRA!
echo !filename!
echo rename "!folder!\!FILE!" "!filename!"
that seems to work, but if i change it to receive parameters, it doesn't:
#echo off
setlocal EnableExtensions EnableDelayedExpansion
set "FILE=%1"
set "ext=%2"
set "folder=%3"
for /F "tokens=1,* delims=0123456789" %%A in ("!FILE!") do (set "EXTRA=%%B")
set "FIRST=!FILE:%EXTRA%=!"
set "filename=!FIRST!.!ext!"
echo !EXTRA!
echo !filename!
echo rename "!folder!\!FILE!" "!filename!"
where %1 is the filename, %2 is the extension and %3 is the folder in which the files are. Probably, the extension can be extracted inside the batch, but i don't know how to do it.
On another hand, i plan to use this batch into another one. There, there will be a for loop in (*.txt) and i don't know how to differentiate between files that have extra things (and then call this batch) from files that doesn't (and then not call this batch).
Regards,

Answer 1

use your method to extract the "extra-portion". In a second step, remove that extra-portion:
#echo off
setlocal enabledelayedexpansion
set "FILE=file name 11 con sosas extras 2.txt"
for /f "tokens=1,* delims=1234567890" %%a in ("%file%") do set new=!file:%%b=!%%~xb
echo %new%
%%~xb gives you the extension.

Answer 2

Here is a batch script that seeks the first purely numeric string portion enclosed within SPACEs, or in case it appears at the end, preceded by a SPACE, that occurs after some other text not consisting of SPACEs only. The part in front of the found number followed by a SPACE followed by the number itself are used for building the new file name.
This approach handles all valid characters for file names properly, even ^, &, %, !, ( and ).
So here is the code:
#echo off
setlocal EnableExtensions DisableDelayedExpansion
rem // Define constants here:
set "_SOURCE=.\test"
for /F "eol=| delims=" %%F in ('
dir /B "%_SOURCE%\*.ext" ^| findstr /R /I ^
/C:"^..* [0123456789][0123456789]*\.ext$" ^
/C:"^..* [0123456789][0123456789]* .*\.ext$"
') do (
set "FILE=%%F"
call :SPLIT FIRST NUM REST "%%~nF"
if defined NUM (
setlocal EnableDelayedExpansion
ECHO rename "!_SOURCE!\!FILE!" "!FIRST! !NUM!%%~xF"
endlocal
)
)
endlocal
exit /B
:SPLIT rtn_first rtn_num rtn_rest val_string
setlocal DisableDelayedExpansion
set "RMD=" & set "NUM=" & set "STR=%~4"
:LOOP
for /F "tokens=1,2,* delims= " %%I in ("%STR%") do (
if not "%%J"=="" (
(for /F "delims=0123456789" %%L in ("%%J") do rem/) && (
if not "%%K"=="" (
set "STR=%%J %%K"
goto :LOOP
)
) || (
set "NUM=%%J"
if not "%%K"=="" (
set "RMD=%%K"
)
)
)
)
set "STR=%~4"
if not defined NUM goto :QUIT
set "STR=%STR% "
call set "STR=%%STR: %NUM% =|%%"
for /F "delims=|" %%L in ("%STR:^^=^%") do set "STR=%%L"
:QUIT
(
endlocal
set "%~1=%STR%"
set "%~2=%NUM%"
set "%~3=%RMD%"
)
exit /B
After having tested the script, remove the upper-case ECHO command to actually rename any files.