Re: Compare two array's

From: John W. Krahn (krahnj_at_acm.org)
Date: 01/07/04 

To: beginners@perl.org
Date: Wed, 07 Jan 2004 02:17:18 -0800

Jerry Preston wrote:
>
> Hi!,

Hello,

> I know that this is a no brainer, but I cannot not get it! I want to
> compare two arrays and delete the same values in one array.
>
> foreach $j ( @a1 ) {
> foreach $p ( @a2 ) {
> $a2[ $p ] = undef if $a1[ $j ] == $a2 $p ];
> }
> }
>
> What is wrong and is there a better, PERL way to do this?

No, but there is a Perl way to do it: :-)

@a2 = do {
    my %seen;
    @seen{ @a1 } = ( 1 ) x @a1;
    grep !$seen{ $_ }, @a2;
    };

John 

-- 
use Perl;
program
fulfillment

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