Hello fellow monks and novitiates. What Soko is asking for is a hash that allows for duplicate keys. If you have had any experience with the SGI version of the STL C++ library, you will know exactly what Soko wants. I have looked at the same problem and walked away disappointed. Perl does not give you this capability for free. Here is a small program that illustrates Soko's problem: 
use English; use strict; 
my $key; my $value;
print "HASH WITH DUPLICATES...\n";
my %mapdup =
(
    1  => "one", 2  => "two",  5  => "five",    # English
    1  => "un",  2  => "deux", 5  => "cinq",    # French
    1  => "ein", 2  => "zwei", 5  => "funf",    # German
    1  => "bir", 2  => "iki",  5  => "bes",     # Turkish
    1  => "yi",  2  => "er",   5  => "wu",      # Mandarin 
);
while (($key, $value) = each %mapdup)
{
    print "($key, $value)\n"  if defined $value;
    print "($key, <undef>)\n" if not defined $value;
}

[download]
What Soko wants is that when he looks up a hash entry using a specific key, 5 for example, he gets multiple values. Perl does not do this. Instead, he gets the most recently defined value for key 5, "wu" in this instance. The others are gone.

Allowing hashes with duplicate keys would be a great way to improve Perl. For now, we have to work around its limitations to acheive the same result. Here are some things that you could try. Adding to and removing values from these hash entries is left as an exercise for the reader. :-) You may want to look at the perllol and perldsc manpages. 

use English; use strict;
my $key; my $value; my $i;
print "\nHASH OF LISTS\n";
my %maplist =
(
    1  => [ ("one", "un", "ein")            ],
    2  => [ ("deux", "er", "two")           ],
    5  => [ ("five", "cinq", "bes", "funf") ],
);
while (($key, $value) = each %maplist)
{
    print "($key, @{$value})\n"  if defined $value;
    print "($key, <undef>)\n" if not defined $value;
}
print "\nHASH OF ARRAYS\n";
my %maparray =
(
    1  => ["one",  "yi"],
    2  => ["zwei", "iki", "two"],
    5  => ["cinq", "five"],
);
print "\n";
foreach my $elem (sort(keys %maparray))
{
    print "$elem: @{$maparray{$elem}}\n";
}
print "\nHASH OF HASHES\n";
my %mapmap =
(
     1 => { english => "one",  french  => "un",   turkish  => "bir"  }
+,
     2 => { french  => "duex", english => "two",  mandarin => "er"   }
+,
     5 => { german  => "funf", french  => "cinq", english  => "five" }
+,
);
print "\n";
foreach my $elem ( sort {$a <=> $b} (keys %mapmap) )
{
    print "$elem: { ";
    foreach my $item (sort keys %{$mapmap{$elem}})
    {
        print "$item=$mapmap{$elem}{$item} ";
    }
    print "}\n";
}

[download]

In reply to Re: 2 dimensional array sorting... by Anonymous Monk
in thread 2 dimensional array sorting... by Soko

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