use Tie::IxHash;

my %th;

tie %th => "Tie::IxHash", qw/ foo bar baz quux /;
print %th, $/;
@th{qw/one three/} = qw/two four/;
print %th, $/;

__output__

foobarbazquux
foobarbazquuxonetwothreefour
[download]

_________
broquaint

For full control over the sort order, the ability to change it on the fly, and a bunch of other bells and whistles I would recommend Tie::Hash::Sorted.

Cheers - L~R

$hash{$_} = { content => $hash{$_}, position => $i++ } for sort keys %
+hash;
[download]

That would use a lot of memory. If I would need something like:

$hash{$_} = { content => $hash{$_}, position => $i++ } for sort keys %
+hash;
[download]

I would do it like this:

$hash{$_} = pack( 'N',$i++).$hash{$_} for sort keys %hash;
[download]

in other words, prefix the ordinal number packed at the beginning of the string. Then, when you either need the linenumber and/or the original string, use unpack:

my ($line,$string) = unpack( 'Na*',$hash{$key} );
[download]

Liz

Wouldn't this kill any chance of using leading digits in keys ({ '34' => 'thirty four' })? And take a significant runtime hit to pack and unpack accordingly?

Tie::IxHash is already done. Does this not serve the purposes required?

--
[ e d @ h a l l e y . c c ]

I would use Tie::IxHash or something like it, but here's a possibility not mentioned:

For everything you insert into the hash, keep an array by its side. You can then use it in a hash slice. Example:

my %hash;
my @hash_array;
$hash{key1} = 'value1';
push @hash_array, 'key1';
$hash{key2} = 'value2';
push @hash_array, 'key2';

. . . 

# Fetch the values. Notice that '%hash' has 
# an array sigil.
my @values = @hash{@hash_array};
[download]

----
I wanted to explore how Perl's closures can be manipulated, and ended up creating an object system by accident.
-- Schemer

Note: All code is untested, unless otherwise stated