#!/usr/bin/perl
use warnings;

my $string = "one=1,three=3,five=5";

%f=map {m/(\w+)=(.*)/} split /,/, $string;

use Data::Dumper;
print Dumper(\%f);

#prints
$VAR1 = {
          'three' => '3',
          'five' => '5',
          'one' => '1'
        };