CODEWITHSUNDEEP
perl
qrbaQ
qrbaQ

Reputation: 1637

Comparing 2 arrays in Perl

Could someone provide a good /nice solution in Perl for comparing 2 arrays (a and b) which check if every element on array a is found in array b (and found only once in array b)?

Upvotes: 0

Views: 325

Answers (2)

Chas. Owens
Chas. Owens

Reputation: 64919

Do you care if and item is b that not in a? The way you have it phrased b can have more items than a. Also, you need to specify what happens when an item is duplicated in an array. Here is some code that finds if there is at least one of every item in a in b: 

#!/usr/bin/perl

use strict;
use warnings;

sub all_in_second {
    my ($first, $second) = @_;
    my %in_second        = map { $_ => 1 } @$second;

    for my $item (@$first) {
        return 0 unless $in_second{$item};
    }
    return 1;
}

my @a = (1, 2, 3, 3, 4);
my @b = (1, 2, 3, 4, 5);

print all_in_second(\(@a, @b)) ? "true" : "false", "\n";

@a = (1, 2, 3, 3, 6);
@b = (1, 2, 3, 4, 5);

print all_in_second(\(@a, @b)) ? "true" : "false", "\n";

Upvotes: 1

Michael Carman
Michael Carman

Reputation: 30831

See perlfaq4:

Upvotes: 9

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