hash keys are stored unsorted. If you have the following hash
%test = ( one => 1,
two => 2,
three => 3);
and print out the hash key/value pairs.
foreach $key (keys %test) {
print "$key is $test{$key}\n";
}
you will find they don't come out in the same order as they were stored.
You can perform a sort on the keys to arrange them in order
foreach $key (sort keys %test) {
print "$key is $test{$key}\n";
}
or you can reverse the hash, making the values the keys, and sort on the new
keys
%reversed = reverse %test;
foreach $key (keys %reversed) {
print "$key is $reversed{$key}\n";
}
In doing this though, you must be aware that you will lose any data that has
identical values. For example
%test = ( one => 1,
two => 2,
three => 3,
alpha => 1,
beta => 2,
gamma => 3);
%reversed = reverse %test;
foreach $key (keys %reversed) {
print "$key is $reversed{$key}\n";
}
will print out
1 is one
2 is two
3 is three
There is probably another/better way of doing this using the comparison
operator <=>, but I don't know it. There is also a module available that
lets you store and retrieve hashes in a fixed order.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
Sent: 26 February 2002 09:16
To: [EMAIL PROTECTED]
Subject: sort order of hash keys
hi
i would like to know if theres a smart way to unwind a hashtable so that
the key / value pairs comes out in the same order as they are in the table.
:o)
martin
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