You need the Schwartzian Transform. If you do a search or super search on sorting you will find an abundance of nodes. You could also look up the the Orcish Manouver (a pun on or cache). There is also a great paper on sorting A Fresh Look at Efficient Perl Sorting

Update

As merlyn points out below you do not need Schwartzian/Orcish as your sort keys are already there. If you have a large amount of data to sort you may get some efficiency gain from the "Packed Default" method in the Guttman & Rosler paper A Fresh Look at Efficient Perl Sorting Here is an example of the Packed Default method ... 
%hash=( 1 => [ 51, 'a2'], 2 => [42, 'a1'] );

print "$_ => @{$hash{$_}}" for 
    map substr($_,2), 
    sort map {pack("C2", $hash{$_}[0])."$_"} 
    keys %hash;

[download]
but for simplicity go for one of the solutions below.

Cheers,
R.

Pereant, qui ante nos nostra dixerunt!

In reply to Re: Sorting a hash of arrays based on a particular array element. by Random_Walk
in thread Sorting a hash of arrays based on a particular array element. by aditya.singh

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