Re: Custom, Reusable Sort Subroutine for Hashes?

#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

sub sort_hash (&\%) {
    my ($sub, $hash) = @_;
    sort {
        local($a, $b) = @$hash{$a, $b};
        $sub->()
    } keys %$hash
}

my %hash = ( second => 2, fourth => 4, third => 3, first => 1 );
say for sort_hash { $a <=> $b } %hash;
[download]

I used a prototype to make the syntax of sort_hash similar to that of sort. The trick is replacing the magical variables $a and $b with the respective values from the hash.

Update: explanation added.

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
[download]

Comment on Re: Custom, Reusable Sort Subroutine for Hashes? Select or Download Code

Replies are listed 'Best First'.
Re^2: Custom, Reusable Sort Subroutine for Hashes? by QM (Parson) on Aug 30, 2017 at 12:45 UTC
This is very good, thanks. Just as an extension, can I use this with a named sort sub? I expect so, but I'll have to go off and experiment. -QM -- Quantum Mechanics: The dreams stuff is made of	[reply]
Re^3: Custom, Reusable Sort Subroutine for Hashes? by choroba (Bishop) on Aug 30, 2017 at 12:56 UTC
> can I use this with a named sort sub? Sure, but you can't use the nice syntax anymore: `sub numerically { $a <=> $b } say for sort_hash(\&numerically, %hash);` [download] ($q=q:Sq=~/;[c](.)(.)/;chr(-\|\|-\|5+lengthSq)`"S\|oS2"`map{chr \|+ord }map{substrSq`S_+\|`\|}3E\|-\|`7**2-3:)=~y+S\|`+$1,++print+eval$q,q,a, [download]	[reply] [d/l] [select]
Re^4: Custom, Reusable Sort Subroutine for Hashes? by LanX (Archbishop) on Aug 30, 2017 at 15:41 UTC
> but you can't use the nice syntax anymore: > `say for sort_hash(\&numerically, %hash);` well you don't need the braces `say for sort_hash \&numerically, %hash ;` and this works too `say for sort_hash {numerically} %hash ;` Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :) Je suis Charlie!}	[reply] [d/l] [select]


more useful options
	PerlMonks