keys of hash of reference to hash

[melguin]

I'm trying to get all of the keys in a referenced hash of a hash. Here's my code:

foreach my $pid (keys %$matches) { 
        foreach my $key (keys $$matches{$pid}) {
               print "$pid:$key:$$matches{$pid}{$key}\n";
        }
}

The error code tells me that it's not a hash. What is the correct syntax?

thanks as always,

melguin

[sauoq]

I think you want your second foreach to look more like:

    foreach my $key (keys %{$matches->{$pid}}) { ... }

-sauoq
"My two cents aren't worth a dime.";

[elusion]

Short answer:
foreach my $key (keys %{$matches->{$pid}}) {

Long answer:
You can think of $matches->{$pid} as the name of your hash. So now that you have the name, you put the hash symbol (%) in front and wrap it in curly braces to disambiguate, and you're all set.

elusion : http://matt.diephouse.com

[melguin]

Shout praises to the all-mighty {}!!!

[Ovid]

#!/usr/bin/perl -w
use strict;

my $matches = {
    foo => { 1 => 'one', 2 => 'two' },
    bar => { this => 'that' }
};

while ( my ($pid,$pid_values) = each %$matches ) {
    while ( my ($key, $value) = each %$pid_values ) {
        print "$pid:$key:$value\n";
    }
}

Cheers,
Ovid

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