sorting array of arrays

[Anonymous Monk]

Hi all, I am trying to sort an array of arrays, but i am stuck. I have red some sources on the internet, but it is not helping me enough. I hope someone can tell me why i am failing. I am trying to sort this array on the second element. Here is the code:

@ar = ([1,12],[8,3],[4,57],[22,5]);
@sort = sort{$a[1]<=>$b[1]}@ar;
foreach (@sort){
    print "@$_\n";}

The desired output is: 8,3 22,5 1,12 4,57. But all i'm getting is the same sorting as i started with. Tx in advance.

[hippo]

Your sorting code treats each element of @ar as an array when it is instead an array ref. Using warnings would have alerted you to that.

@ar = ([1,12],[8,3],[4,57],[22,5]);
@sort = sort{$a->[1]<=>$b->[1]}@ar;
foreach (@sort){
    print "@$_\n";
}

[Anonymous Monk]

Tx.

[AnomalousMonk]

Further to hippo's post:   Note that going a step further and enabling strictures with  usestrict; would have prevented the code from compiling in the first place:

c:\@Work\Perl\monks>perl -le
"use strict;
 use warnings;
 ;;
 my @ar = ([1,12],[8,3],[4,57],[22,5]);
 my @sort = sort{$a[1]<=>$b[1]}@ar;
 foreach (@sort){
     print \"@$_\n\";}
"
Global symbol "@a" requires explicit package name at -e line 1.
Global symbol "@b" requires explicit package name at -e line 1.
Execution of -e aborted due to compilation errors.

(I have to admit the  Global symbol "@a" requires explicit package name ... etc messages are slightly more obscure, but they explicitly point you to the offending variable.)

See also How do I sort an array by (anything)? in the Data: Arrays section of perlfaq4.

[fanasy]

you miss "->"

use strict;
 use warnings;
 ;;
 my @ar = ([1,12],[8,3],[4,57],[22,5]);
 my @sort = sort{$a->[1]<=>$b->[1]}@ar;
 foreach (@sort){
     print "@$_\n";}

PS D:\perl\perlmonks> perl .\sort.pl
8 3
22 5
1 12
4 57

[AnomalousMonk]

But the point of my post and part of the point of hippo's before it is that if warnings and/or strict had been used, Perl would not have, so to speak, "missed" the  -> operator.

Update: Oh... Or did you mean to respond to the OP?