Hi, I need to sort a two dimensional array (@twodarray) that looks something like: 
    [0]  [1]
[0] chr1 10 
[1] chr3 20 
[2] chr1 30 
[3] chr3 5     
.
.
.
[n] chr5 5

[download]
first by chr number (all chr1 go first, then all chr3, then all chr5, etc.) and within that by column 1 in ascending order. that is, the resulting array should look like that: 
    [0]  [1]
[0] chr1 10 
[1] chr1 30 
[2] chr3 5 
[3] chr3 20     
.
.
.
[n] chr5 5

[download]
the code I'm trying to use is: 
my @sortedtda;
my @chrnums;
my @coords;
$i=0;

for (@twodarray) {
    push @chrnums, $twodarray[$i][0]=~ (/(\d+)/);
    push @coords,  $twodarray[$i][1]=~ (/(\d+)/);
    ++$i;
    }

@sortedtda = @twodarray[ sort {
            $coords[$a] <=> $coords[$b]
                 ||
            $chrnums[$a] <=> $chrnums[$b]
               } 0..$#twodarray
           ];

[download]
For a small dataset, it seems to work okay, but for real data the result is somewhat random - perhaps my test dataset is just biased. Is there some kind of mistake or the whole thing doesn't make any sense at all? I would really appreciate any help. Thanks in advance!

In reply to Sorting a two-dimensional array by two columns by a11

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