Sorting custom dates in Perl -

i have hash keys being dates:

my %dates = ( 'may 13, 2015' => 8, 'may 7, 2015' => 1, 'apr 29, 2015' => 2, 'may 12, 2015' => 1, 'apr 16, 2015' => 13, 'may 6, 2015' => 1, ); 

i'm trying sort them date. i've tried 2 ways:

foreach $k (sort {join('', (split ' ', $a)[2,0,1]) <=> join('', (split ' ', $a)[2,0,1])} keys(%dates))  { print $k . " = " . $dates{$k}; } 

which doesn't work since month string, , this:

foreach $k (sort {join('', (split ' ', $a)[2,0,1]) cmp join('', (split ' ', $a)[2,0,1])} keys(%dates))  { print $k . " = " . $dates{$k}; } 

doesn't work either, puts apr first may. has idea on how fix it?

you can parse dates using time::piece

#!/usr/bin/env perl  use strict; use warnings;  use time::piece;  %dates = (     'may 13, 2015' => 8,     'may 7, 2015' => 1,     'apr 29, 2015' => 2,     'may 12, 2015' => 1,     'apr 16, 2015' => 13,     'may 6, 2015' => 1, );  $k (sort by_date keys %dates) {     print "$k => $dates{$k}\n"; }  sub by_date {     ($ta, $tb) = map time::piece->strptime($_, '%b %d, %y'), $a, $b;     $ta <=> $tb; } 

output:

apr 16, 2015 => 13 apr 29, 2015 => 2  may 6, 2015 => 1   may 7, 2015 => 1   may 12, 2015 => 1  may 13, 2015 => 8

of course, if wanted give benefits of time::piece, along following lines:

#!/usr/bin/env perl  use 5.010; use strict; use warnings;  %dates = (     'may 13, 2015' => 8,     'may 7, 2015' => 1,     'apr 29, 2015' => 2,     'may 12, 2015' => 1,     'apr 16, 2015' => 13,     'may 6, 2015' => 1, );  $k (sort by_ugliness keys %dates) {     print "$k => $dates{$k}\n"; }  sub by_ugliness {     state $months = {         {             $i = 1;             map {$_ => $i++}             qw(jan feb mar apr may jun jul aug sep oct nov dec)         }     };      ($ta, $tb) = map [         /\a (\s+) \s+ ([0-9]{1,2}), \s+ ([0-9]{4})\z/x     ], $a, $b;      ($ta->[2] <=> $tb->[2]) ||     ($months->{ $ta->[0] } <=> $months->{ $tb->[0]}) ||     ($ta->[1] <=> $tb->[1]) ; } 

at point, going start refining pattern match. don't ;-)