Re: Hash assignments using map

Here's another way to do what you want, without creating an intermediate %keepers hash:

use strict;
use warnings;

use Data::Dumper;

# Data Structure
my %h = (
    'a' => 'z',
    'b' => 'y',
    'c' => 'x',
    'd' => 'w',
);

my @to_keep = qw{ a c };

%h = map { $_ => $h{$_} } @to_keep;

print Dumper \%h;
[download]

Update: If by chance your @to_keep array might contain elements that do not necessarily occur as keys in your input hash, it would probably be better to change the penultimate line to:

%h = map { $_ => $h{$_} } grep { defined $h{$_} } @to_keep;

Comment on Re: Hash assignments using map Select or Download Code

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Re^2: Hash assignments using map by njcodewarrior (Pilgrim) on Feb 25, 2007 at 13:41 UTC
Hello there Not a Number That's very nice and simple! Thanks very much for your help! - njcodewarrior	[reply]
Re^2: Hash assignments using map by ikegami (Patriarch) on Feb 25, 2007 at 18:58 UTC
`%h = map { $_ => $h{$_} } @to_keep;` is the same as ~~`%h = @h{@to_keep};`~~ Update: Oops, no! It would actually be equivalent to the more complicated: `my %temp; @temp{@to_keep} = @h{@to_keep}; %h = %temp;` [download]	[reply] [d/l] [select]