This is more or less directly from the Perl Cookbook It passes through the first array remembering all elements in the 'seen' hash, then passes through the second one and only remembers the elements already encountered in the first.

It also has a more idomatic version there if you want is more perlish.

 
use strict;
use warnings;

my @a = (1, 3, 5, 6, 7, 8);
my @b = (2, 3, 5, 7, 9);

my (@isect, %seen, %isect);

foreach my $e (@a) { $seen{$e} = 1 }

foreach my $e (@b) {
    if ( $seen{$e} ) { $isect{$e} = 1 }
}

@isect = keys %isect;

print "@isect\n";

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cheers

si_lence

In reply to Re: comparing two array by si_lence
in thread comparing two array by paola82

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