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Sorting an array

rkk
New User

Jun 14, 2013, 3:23 PM

Post #1 of 2 (2979 views)

Sorting an array	Can't Post

Hello,

I need some suggestion regarding sorting an array.

Ex:

@arr=(100,20,3,45,1);
#To sort the above array I did
@index=sort{ $arr2[$a] <=> $arr2[$b] } 0 .. $#arr;
print @index;

Output:

4 2 1 3 0

[download]
But, if I have an array like the following

@arr=((ch1,100), (ch2,20), (ch1,13), (ch2,45), (ch1,1));

How to sort this kind of array (first sort first element and then sort by second element)

Sample output should be,

4 0 2 1 3

Any suggestions, please advise.

Thanks,

BillKSmith
Veteran

Jun 15, 2013, 7:18 AM

Post #2 of 2 (2966 views)

Re: [rkk] Sorting an array [In reply to]	Can't Post

Perl would ignore the parenthesis in your second array. I assume that you intend an array of arrays. Your expected output is not consistent with my interpretation. Here is what I have.

Code

use strict; 
use warnings; 
use Readonly; 
Readonly::Array my @arr2 => 
    ( 
        ['ch1', 100], 
        ['ch2',  20], 
        ['ch1',  13], 
        ['ch2',  45], 
        ['ch1',   1] 
    ); 
my @index = sort {     $arr2[$a][0] cmp $arr2[$b][0]  
                    or $arr2[$a][1] <=> $arr2[$b][1] 
                 } 0 .. $#arr2; 
print "@index\n";

OUTPUT: 4 2 0 1 3

UPDATE: Please refer to cross posts. This question was already answered on perlmonks
Good Luck,
Bill

(This post was edited by BillKSmith on Jun 15, 2013, 7:37 AM)

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