map returns a list so the solution to your missing value conundrum is to return an empty list for suppressed values. I'm not sure I'd solve this particular problem using a map and the following technique, but the technique is worth knowing about in any case:

use strict;
use warnings;

my %info = map {chomp; my @parts = split '=';
    @parts == 2 && length $parts[1] ? @parts : ()
    } <DATA>;

print "$_: $info{$_}\n" for sort keys %info;

__DATA__
key=value
nokey=

[download]

Prints:

key: value

[download]
True laziness is hard work

In reply to Re: map a hash with a default value or exclude by GrandFather
in thread map a hash with a default value or exclude by kayahk

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