Re: Passing hashes to subs?

You can use

&callsub(%hashtopass); 

sub callsub {
   %hashread = @_;

   foreach $k (keys %hashread) {
       print "$k => $hashread{$k}\n";
   }
}
[download]

but I prefer to use references:

&callsub(\%hashtopass, $otherStuff);

sub callsub {
   my ($hashref, $otherParam) = @_; 
# or: my $hashref = shift; if you prefer that

   foreach my $k (keys %{$hashref}) {
       print "$k => $hashref->{$k}\n";
   }
}
[download]

This way, you can even pass along other parameters.

Comment on Re: Passing hashes to subs? Select or Download Code

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Re: Re: Passing hashes to subs? by Chady (Priest) on Aug 01, 2002 at 12:33 UTC
`&callsub(%hashtopass); sub callsub { %hashread = @_;` [download] I don't think this is good practice.. what if you decide to pass a scalar along with that and forgot to shift it out before assigning the list to the hash? you might end up with a corrupted list, or worst, a legitimate list with wrong values shooting yourself in the foot. He who asks will be a fool for five minutes, but he who doesn't ask will remain a fool for life. Chady \| http://chady.net/	[reply] [d/l]
Re: Passing hashes to subs? by crenz (Priest) on Aug 01, 2002 at 12:46 UTC
Yes, that's why I suggested the second approach using references. But I neglected to point out the dangers to the original poster. Thanks! FWIW, I do like to use it if (and only if...) the function is designed to receive only named parameters. E. g. `sub create { my $self = shift; my %p = @_; print "$p{color} p{animal}" for (1..$p{count}); } $zoo->create(animal => 'camel', count => '10', color => 'green');` [download] One could opt to create the zoo using a hash reference as in `$zoo->create({animal => 'monkey', ...});` but I guess that is a matter of style.	[reply] [d/l] [select]