#!/usr/bin/perl -w
use strict;
my @temp=("a_1","b_1","a_2","a_3","a_4","b_2","a_5","b_3","a_6","b_4");

my (@a, @b) ;

my %dispatch = 
(
	"a" => sub { push @a, shift },
	"b" => sub { push @b, shift },
);


foreach my $value (@temp) 
{

	if ( $value =~ /^([ab])_(.+)$/ )
	{
		my $sub = $dispatch{$1};
		&$sub($2);
	}
}

print "@a <==> @b\n";