You could also try a Guttman Rosler transform. This melds the fields to sort and the whole item into a single string that can be sorted lexically. The original item can then be pulled from the sorted string afterwards. pack or sprintf are often used to construct the string. Care has to be taken to make sure the fields pack to a consistent length across all of the list to be sorted!

use strict;
use warnings;

my @list = qw{ a1_2 a1_1 a10_10 a2_10 a2_1 a2_2 a10_1 a10_2 a1_10 };

my @sorted =
   map { substr $_, 8 }
   sort
   map { pack q{NNa*}, m{(\d+)_(\d+)}, $_ }
   @list;

print qq{$_\n} for @sorted;

[download]

The output.

a1_1
a1_2
a1_10
a2_1
a2_2
a2_10
a10_1
a10_2
a10_10

[download]

I hope this is of interest.

Cheers,

JohnGG

In reply to Re: Sort problems by johngg
in thread Sort problems by erez_ez

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