Cruel references

Hello wise monks,

please, look at this sample code.

#!/usr/bin/perl
use strict;
use warnings;
my %pets;
my $color;

$color="black";
$pets{$color}=\[];
push @${$pets{$color}},"cat";
push @${$pets{$color}},"dog";

$color="while";
$pets{$color}=\[];
push @${$pets{$color}},"rat";
push @${$pets{$color}},"bat";

foreach my $p (values %pets) {
        print "$p\n";
        #^^^this is ref to ref to array?

        print "$$p\n";
        #^^^this is ref to array

        print "@$$p\n\n";
        #^^^this is array
}
[download]

and output:

push @${$pets{$color}},"rat";
REF(0x815c4d0)
ARRAY(0x815c4e8)
rat bat

REF(0x812ed0c)
ARRAY(0x812ed48)
cat dog
[download]

@$$p looks very strange.
why I can't use @$p.
why $p is ref to ref to array (or maybe is not?) not just ref to array?
I don't understand this. Could anybody help me?

stay in peace
Lukasz

Comment on Cruel references Select or Download Code
Re: Cruel references by japhy (Canon) on Mar 06, 2005 at 00:27 UTC
It's because you have `\[]` instead of just `[]`. `[]` is a reference to an anonymous array, and `\[]` is a reference TO a reference to an anonymous array. _____________________________________________________ Jeff `japhy` Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and `perl` hacker How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart	[reply] [d/l] [select]
Re^2: Cruel references by uksza (Monsignor) on Mar 06, 2005 at 00:51 UTC
of course!! Thanks a lot! This is right way: `$pets{$color}=[]; push @{$pets{$color}},"cat";` [download]	[reply] [d/l]
Re: Cruel references by trammell (Priest) on Mar 06, 2005 at 00:53 UTC
You probably mean (or want): `... my %pets; my $color = 'black'; # $pets{$color} = []; # this line is unnecessary push @{ $pets{$color} }, 'cat'; push @{ $pets{$color} }, 'dog'; foreach my $p (values %pets) { print "@$p\n"; }` [download]	[reply] [d/l]


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Cruel references

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