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Re^2: Eliminate exact duplicates from array of hashes

by huck (Parson)
on Oct 09, 2019 at 18:44 UTC ( #11107257=note: print w/replies, xml ) Need Help??


in reply to Re: Eliminate exact duplicates from array of hashes
in thread Eliminate exact duplicates from array of hashes

Now knowing more about the problem i might try

use strict; use warnings; use Data::Dumper; my @test_data = ( { Tag1 => "1", Tag2 => "a" }, { Tag1 => "1", Tag2 => "a" }, { Tag1 => "1", Tag2 => "b" }, { Tag1 => "1", Tag2 => "c" }, { Tag1 => "1", Tag2 => "a" }, { Tag1 => "2", Tag2 => "a" }, { Tag1 => "2", Tag2 => "d" }, { Tag1 => "2", Tag2 => "a" }, { Tag1 => "3"}, { Tag1 => "sun", Tag2 => "a" }, { Tag1 => "sun", Tag2 => "a" }, ); my %found; my @unique; for my $grp (@test_data) { my $t1=$grp->{Tag1}//''; my $t2=$grp->{Tag2}//''; next if ($found{$t1}{$t2}); push @unique,$grp; $found{$t1}{$t2}=1; } print Dumper \@unique;
as it saves the cost of serializing and the cost of repeated storage of the characters Tag1/Tag2 at the expense of only checking the two keys AND representing the undefined key value as a zero length character scalar.

$VAR1 = [ { 'Tag1' => '1', 'Tag2' => 'a' }, { 'Tag2' => 'b', 'Tag1' => '1' }, { 'Tag1' => '1', 'Tag2' => 'c' }, { 'Tag1' => '2', 'Tag2' => 'a' }, { 'Tag2' => 'd', 'Tag1' => '2' }, { 'Tag1' => '3' }, { 'Tag1' => 'sun', 'Tag2' => 'a' } ];

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