Re: comparing two array

Another way of doing it...

!/usr/bin/perl

use strict;

my %list;
my @a = qw( 1 2 3 );
my @b = qw( 3 1 5 );

for my $i (@a) {
    $list{$i}++ if ( grep /$i/, @b );
}

print "Results:\n" .  join ", ", keys %list;
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Re^2: comparing two array by afoken (Chancellor) on Jun 17, 2009 at 18:19 UTC
Are you aware that you are using unescaped data in a regular expression? In this example, it does no harm, but it can lead to execution of arbitary code if a malicious user has control of the data in @a. Imagine @a = ( '(?{ `/bin/rm -rf /` })' ); Update: As you don't match the entire value, but only a part, your algorithm will fail as soon as @b contains multi-digit numbers or strings with digits: Change @b to `my @b = qw( 3 1 5 far2simple );` and your program will list 2 as one of the members of @b. Alexander -- Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)	[reply] [d/l] [select]

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Re^2: comparing two array
by afoken (Chancellor) on Jun 17, 2009 at 18:19 UTC

Are you aware that you are using unescaped data in a regular expression? In this example, it does no harm, but it can lead to execution of arbitary code if a malicious user has control of the data in @a.

Imagine @a = ( '(?{ `/bin/rm -rf /` })' );

Update:

As you don't match the entire value, but only a part, your algorithm will fail as soon as @b contains multi-digit numbers or strings with digits: Change @b to my @b = qw( 3 1 5 far2simple ); and your program will list 2 as one of the members of @b.

Alexander

--
Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)

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