I have the following code snippet which should sort the the @x array on the 2nd element of $x[], but instead it dies with the following message. 
Modification of a read-only value attempted at a.pl line 8.

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#!/usr/bin/perl -w
$x[1][1]=11;
$x[1][2]=12;
$x[1][3]=13;
$x[2][1]=21;
$x[2][2]=22;
$x[2][3]=23;
@sorted = sort {$b->[2]cmp $a->[2] } @x;

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Debugging revealed that I can access $b->[2] ok but whenever I attempt to dereference the $a variable it dies as above. The same thing happens if I use the  $$a[2] syntax instead of $a->{2]. Any perls of wisdom would be much appreciated.

Edit by tye, remove PRE tags

In reply to how to sort multi-dimensional arrays by Anonymous Monk

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