You might want to look at Tie::DxHash. I think this does what you want. Tie::IxHash only allows one value per key - Tie::DxHash allows duplicate keys although the documentation is not so good.

Untested code: 
use strict;
use Tie::DxHash;

my %foo;
tie %foo, 'Tie::DxHash';

%foo = qw (    one 1.2
               one 1.6
               one 1.9
               two 2
               three 3 );
my @keys = keys %foo;
print "@keys\n";

# if @keys only has each key once, try this:
foreach my $key (@keys)
{
    print "$key, " foreach ($foo{$key})
}

[download]
Try it and see what happens - if it doesn't work, you might want to take another look at what you're doing and see if you can do whatever you're trying to do. Perhaps maintain a seperate count every time you add\delete a value.

Update: You don't really need a module to do this. Have a look at perldsc. You can create a type of hash that allows multiple values - a hash of arrays - i.e. each hash key points to an anonymous array. It would look like this: 
%hash = ( one => [1.2, 1.6, 1.9],
          two => [2],
          three => [3]);

[download]
Look into perldsc anyway because I think this is best method.

Simon Flack ($code or die)
$,=reverse'"ro_';s,$,\$,;s,$,lc ref sub{},e;$,
=~y'_"' ';eval"die";print $_,lc substr$@,0,3;

In reply to Re: Ix::Hash with repeated keys by $code or die
in thread Ix::Hash with repeated keys by quesada

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