Re^3: 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");
}
[download]

Comment on Re^3: Default Hash Key Download Code

Replies are listed 'Best First'.
Re^4: Default Hash Key by EvanCarroll (Chaplain) on May 02, 2008 at 14:51 UTC
Which is why god invented the '//' operator -- most definitely a better choice than '\|\|' in this context. Evan Carroll I hack for the ladies. www.EvanCarroll.com	[reply]
Re^4: Default Hash Key by matze (Friar) on May 03, 2008 at 12:58 UTC
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 :)	[reply] [d/l] [select]
Re^4: Default Hash Key by Anonymous Monk on May 04, 2008 at 17:10 UTC
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.	[reply]