Re: comparing array elements to hash keys

Much easier with grep.

@new_array = @hash{ grep { exists $hash{$_} } @array };
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Comment on Re: comparing array elements to hash keys Download Code

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Re: Re: comparing array elements to hash keys by dvergin (Monsignor) on Jul 03, 2003 at 19:53 UTC
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]	[reply] [d/l] [select]

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Re: Re: comparing array elements to hash keys
by dvergin (Monsignor) on Jul 03, 2003 at 19:53 UTC

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

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;
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