in reply to Re: optimal way of comparing 2 arrays
in thread optimal way of comparing 2 arrays

Hi Blazar,
No duplicates in these arrays. All values are unique.
thanks
narashima
  • Comment on Re^2: optimal way of comparing 2 arrays

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Re^3: optimal way of comparing 2 arrays
by blazar (Canon) on Oct 20, 2005 at 15:00 UTC
    Then the solution above may be simplified to: 
    #!/usr/bin/perl -l

use strict;
use warnings;

my @file1=qw/foo bar baz/;
my @file2=qw/fred bar barney/;

my %saw;
$saw{$_}++ for @file1, @file2;

print <<"EOT"
\@file1 only: (@{[ grep $saw{$_}==1, @file1 ]})
\@file2 only: (@{[ grep $saw{$_}==1, @file2 ]})
common: (@{[ grep $saw{$_}==2, @file2 ]})
EOT

__END__

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    or even, using modulo-2 math, but more obscurely: 
    #!/usr/bin/perl -l

use strict;
use warnings;

my @file1=qw/foo bar baz/;
my @file2=qw/fred bar barney/;

my %saw;
$saw{$_} ^= 1 for @file1, @file2;

print <<"EOT"
\@file1 only: (@{[ grep $saw{$_}, @file1 ]})
\@file2 only: (@{[ grep $saw{$_}, @file2 ]})
common: (@{[ grep !$saw{$_}, @file2 ]})
EOT

__END__

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