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Re: Re: comparing array elements to hash keys

by dvergin (Monsignor)
on Jul 03, 2003 at 19:53 UTC ( [id://271273]=note: print w/replies, xml ) Need Help??


in reply to Re: comparing array elements to hash keys
in thread comparing array elements to hash keys

I was going to suggest: 
   my @ary2 = grep {defined} @hash{@ary};

[download]
It's tempting to just say   my @ary2 = @hash{@ary}.   But the values in @ary that don't match keys in %hash produce undefined values that have to be weeded out.

Here's a quick demo: 

#!/usr/bin/perl -w
use strict;

my @ary  = ('a', 'c', 'g', 'l');
my %hash = (a => 1, b => 2, c => 3, d => 4);

my @ary2 = grep {defined} @hash{@ary};

print "[$_]\n" for @ary2;

[download]

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