#!/usr/bin/perl use strict; use warnings; use Benchmark qw{cmpthese}; cmpthese( -1 => { no_assignment => sub { for( 1..10_000 ) { my %hash; $hash{$_} = $_; $hash{-$_} = -$_; } }, assignment => sub { for( 1..10_000 ) { my %hash = (); $hash{$_} = $_; $hash{-$_} = -$_; } }, } ); __END__ Rate assignment ano_assignment assignment 99.4/s -- -8% no_assignment 108/s 9% --