Hashes won't preserve order. You can use Tie::IxHash, which sets up a different, order preserving, data structure with hash semantics.

You could keep a sorted array of keys from your hash, instead.

my @key_sorted = sort keys %hash;
#or
my @val_sorted = sort {$hash{$a} cmp $hash{$b}} keys %hash;
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Zaxo,
Tie::IxHash is not designed for hash sorting which this question is about. It does allow you to preserve insertion order so that would require you to know in advance every single key/val pair that you want for the hash and enter them in that order. Ok, it does provide extremely rudimentary sorting capability (asciibetically by keys or vals), but that is more of an afterthought.

If you want your hash to stay sorted using an arbitrary criteria regardless of what you do to it, use Tie::Hash::Sorted.

Cheers - L~R

You need to consider what you really want to do with your data. A hash is a bag that holds a bunch of data that you access using a key. There is no 'order' to the data. In fact, what order it may have will change as data is added and removed from the bag.

If you want fast access to a chunk of data given a key, use a hash. If you want to preserve the order of a list of stuff, use an array. If you want to do both use a tied hash (Tie::IxHash as suggested by Zaxo). Note though that a tied hash does neither job as well as the built in structures.

Most often though all you need is to generate a sorted list of keys when you need them using something like sort keys %hash. If what you want is to sort by the values and don't care about the keys you can sort values %hash. But really, any general advice is likely to be overtaken by your actual application. To get solid advice, provide a small sample of the sort of data and the code that you are using. Mention too how much data there is and how often you may need to access the data in sorted order. All those things influence the choices that may be made.

my %hash;

# use the hash like normal - perl will keep it in whatever
# order is the most useful for the runtime

foreach my $key (sort keys %hash) {
    print $hash{$key};
}
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Thanks, printing it out when needed will do just fine,
however I need to print both the key names and values.
Apologies as I'm new to perl.

however I need to print both the key names and values

Then print both :)

foreach my $key (sort keys %hash) {
    print "$key : $hash{$key}\n";
}
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Update: typo fixed. Thanks to johngg for pointing it out.

--
<http://dave.org.uk>

"The first rule of Perl club is you do not talk about Perl club."
-- Chip Salzenberg

Got it!

Thanks for your patience :)