http://www.perlmonks.org?node_id=1098646

Special_K has asked for the wisdom of the Perl Monks concerning the following question:

I have the following data structure:



$data_hash{$key0}[$idx0]{$key1} = <some floating point value>


I would like to sort this data structure by its values. Currently I am doing this by creating a new hash in which the key is the floating point value, and the value is an array where each element is a concatenation of $key0, $idx0, and $key1. Each value of the new hash has to be an array as opposed to a scalar because the floating point values in the original data structure are not guaranteed to be unique; that is two entries in the original hash of array of hashes could have the same value.

Is there a way to sort this data structure by value without having to create a new hash first? I figure there must be some way to use the sort command with the original data structure, but I can't seem to get it to work. Also if there is a way to sort my original data structure by value using a single sort command, are there any performance implications by doing so compared to the method I am currently using?

Here is the method I am currently using if anyone is curious:



# create a new hash where the key is the value of the original hash, a +nd the value is an array of keys from the original hash that have the + given value foreach $key0 (keys(%data_hash)) { foreach $key1 (keys(%{$data_hash{$key0}})) { for ($i = 0; $i < @{$limit_hash{$key0}{$key1}{'limit'}}; $i++) { push(@{$new_hash{$data_hash{$key0}[$i]{$key1}}}, $key0 . " +__" . $limit_hash{$key0}{$key1}{'limit'}[$i] . "__" . $key1); } } } # now print the new hash that is sorted by value foreach my $sorted_by_val ( sort{$a <=> $b} keys(%new_hash)) { printf("key %.2f: ", $sorted_by_val); foreach my $val (@{$new_hash{$sorted_by_val}}) { printf("$val"); } printf("\n"); }