Re^3: Default Hash Key

[mrons]

in reply to Re^2: Default Hash Key
in thread Default Hash Key

Just be careful about $description{foo} that evaluate to false:

use strict;
use warnings;
my %description = ( a => 'a vowel',
                    b => 'a consonant',
                    0 => '0',
                    default => 'not in the alphabet' );

for my $char (qw/a b c 0/) {
   my $d = $description{$char} || $description{default};
   print("$char is $d\n");
}

[EvanCarroll]

Which is why god invented the '//' operator -- most definitely a better choice than '||' in this context.

[matze]

Which is where the exists used in the first two original replies to the OP comes in handy...

Because of things like this, I find myself using defined and exists a lot when writing code. It may be more verbose but better safe than sorry... I hope I'm not too much of a Captain Obvious :)

[Anonymous Monk]

That problem is avoided in Perl 5.10.0 with my $d = $description{$char} // $description{default}; # check for undefined rather than false As for getting one's head around the logical or, it's really quite simple: $a || $b || $c || ... yields the first value that is true (or false if none are). Perl didn't invent it; it's a common operator in many languages, dating back to Snobol, I think.