#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11124461
use warnings;

my @list = ( '1,cat', '2,dog', '22,mouse', '11,eel', '001,elk', '13,mink');

my @n;
@n[ /(\d+),/ ] .= "$_\n" for @list;
print grep defined, @n;