Hi Monks, I am trying to sort an array using the Schwartzian transform on the first element of num1_num2 
use strict;
my @unsorted = (
                '864278_864377',
                '864518_864703',
                '851171_851270',
                '855398_855579',
                '856258_856357',
                '861015_861139',
                '866387_866549',
                '791806_792296',
               '1088806_1082296',
        );
            

my @sorted = map  { $_->[0] }
          sort { $a->[1] cmp $b->[1] }
          map  { [ $_, ( split(/\_/, $_) )[0] ] }
               @unsorted;

               
               print join ("\n",@sorted);

[download]
I am expecting the sorted array to be in this order: 
791806_792296
851171_851270
855398_855579
856258_856357
861015_861139
864278_864377
864518_864703
1088806_1082296

[download]
Instead I am getting this: 
1088806_1082296
791806_792296
851171_851270
855398_855579
856258_856357
861015_861139
864278_864377
864518_864703
866387_866549

[download]
I just can't figure out how to fix this! Thanks much for your input!
UPDATE: I fixed it by using  <=> numeric sort!

In reply to Sort an array using the Schwartzian transform by umasuresh

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