Re: Hash assignments using map

[Not_a_Number]

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;

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;

[njcodewarrior]

Hello there Not a Number

That's very nice and simple!

Thanks very much for your help! - njcodewarrior

[ikegami]

%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;