uniq by coderef

uniq_by.pl

#!perl
# Usage: my @uniq_array = uniq_by { $_->{key} } @array;
use strict;
use warnings;

use List::Util q(first);
use List::MoreUtils qw(uniq);

sub uniq_by (&@) {
    my ($code, @array) = @_;
    my @rets;
    my %map;
    for my $one (@array) {
        local $_ = $one;
        my $ret = $code->($one);
        push @rets, $ret;
        $map{$ret} = $one;
    }
    my @uniq_keys = uniq @rets;
    map { $map{$_} } @uniq_keys;
}