No, the sorting would not work if they were arrays. Read sort again and you'll see why. Not only that, but hashes are by definition sorted by hash, that is, sorted in a manner only meaningful to the interpreter, probably not to you. However, arrays may or may not be sorted. The problem is that the sort function is non-destructive; it won't sort an array in place, but rather return a new array, which is sorted.

Now as for the second problem, I assume you want to print to TEST the contents of playlist, and TEST2 the contents of filelist, with the keys sorted ASCIIbetically. Then you need two for loops:

for (sort keys %playlist) { print TEST  "$playlist{$_}\n" }
for (sort keys %filelist) { print TEST2 "$filelist{$_}\n" }
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Now if you want the values sorted instead, then you need to do:

for (sort values %playlist) { print TEST  "$_\n" }
for (sort values %filelist) { print TEST2 "$_\n" }
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HTH.

This should work for you, if you wanted it sorted by values. If you wanted keys, just change the first for loop to add keys rather than values to the arrays. Enjoy.

my @files;
my @plays;

for (keys %filelist)
{
    $files[@files] = $filelist{$_};
    $plays[@plays] = $playlist{$_};
}

my @sorted = (0 .. $#files);
@sorted = sort {$files[$a] cmp $files[$b]} @sorted;
@files  = @files[@sorted];
@plays  = @plays[@sorted];

for (my $i=0; $i<@files; $i++)
{
    print "$files[$i]   \<\=\>   $plays[$i]\n"
}
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my @files;
my @plays;

for (keys %filelist)
{
    $files[@files] = $filelist{$_};
    $plays[@plays] = $playlist{$_};
}
[download]

Just a small remark, you don't need a for-loop for that, I'd use values and a hash slice:

my @files = values %filelist;
my @plays = @playlist{ keys %filelist };
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-- Hofmator

You don't actually want to sort two hashes. No really, you said so. You want to compare two hashes. As you say, if a human is comparing them it is easier if they are sorted. But not if the computer is going to do it for you.

Your longer term goal basically wants to take two hashes (%first and %second) as input and list:

• keys in %second not in %first (@additions)
• keys in %first not in %second (@deletions)
• keys in both which have different values (@modifications)

You can get the @additions or @deletions by looping through the keys of one hash and doing 'exists' test on the other. The situation is symettric and so you can write that bit as a helper routine and call it twice.

You can get modifications by looping through the keys of either hash (not both) and doing nothing in the loop if the key is in either of the @additions or @deletions arrays. (You might want to invert the arrays into hashes to make an efficient "is this scalar in this array" test.)

But you don't need the keys sorted in any of the loops described above.

Have fun.

PS. If efficency is your goal you can reduce the number of loops in what I have described above. But hey, optimising pseudo-code-written-in-english could be called premature.

%hash = sort %hash;
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use strict;
use warnings;

my %hash = (
        thing1 => 'one thing',
        thing2 => 'leads to another',
        All    => 'is great and glorious',
    );

print "$_ => $hash{$_}\n" for keys %hash;

%hash = sort %hash;

print "\n";
print "$_ => $hash{$_}\n" for keys %hash;
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thing2 => leads to another
All => is great and glorious
thing1 => one thing

leads to another => one thing
thing1 => thing2
All => is great and glorious
[download]

Goip,
Ira,

"So... What do all these little arrows mean?"
~unknown

For a serious answer, have a look to the Perl FAQ.