Some advice regaring sorting and hashes

tsk1979 has asked for the wisdom of the Perl Monks concerning the following question:

I have a hash which looks somewhat like the example posted below


AA01 => ALPHA = 453
         OMEGA = 43
         COUNT = 44
GF02 => ALPHA = 445
         OMEGA = 4311
         COUNT = 444

...
[download]

So lets say in a text report I am printing it as follows

GROUP    COUNT     ALPHA OMEGA
AA01      44         453   43
GF02      444        445   4311
....
...
[download]

Now the user wants that they should be able to choose the way the report is sorted. If I use

sort keys { $a <=> $b} %hash
[download]

I can sort by the group name. Now what if I want to print the report sorted by COUNT, or ALPHA etc.,

Comment on Some advice regaring sorting and hashes Select or Download Code

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Re: Some advice regaring sorting and hashes by JavaFan (Canon) on Jun 08, 2009 at 11:53 UTC
`my $field = 'COUNT'; sort {$hash{$a}{$field} <=> $hash{$b}{$field}} keys %hash;` [download]	[reply] [d/l]
Re: Some advice regaring sorting and hashes by targetsmart (Curate) on Jun 08, 2009 at 11:55 UTC
you can use hash of arrays for that if your data is like this the inner array is `[count, alpha, omega]` respectively. `$VAR1 = { 'a' => [ 0, 1, 2 ], 'b' => [ -1, 3, 4 ], 'c' => [ 4, 5, 6 ] };` [download] you can use something like below if you want to sort numerically by count `sort { $hash{$a}[0] <=> $hash{$b}[0]} keys %hash` [download] Vivek -- In accordance with the prarabdha of each, the One whose function it is to ordain makes each to act. What will not happen will never happen, whatever effort one may put forth. And what will happen will not fail to happen, however much one may seek to prevent it. This is certain. The part of wisdom therefore is to stay quiet.	[reply] [d/l] [select]
Re: Some advice regaring sorting and hashes by markkawika (Monk) on Jun 08, 2009 at 23:51 UTC
Your code: `sort keys { $a <=> $b } %hash` [download] Is incorrect. Assuming the groups really look like "AA01" and "GF02", and assuming you want them in alphabetical order, and assuming these are in the hash `%hash`, this is what you want: `sort { $a cmp $b } keys %hash` [download]	[reply] [d/l] [select]