sort function in Perl – random output

I’m trying to write a sort function in Perl. I need that "name_iwant_last" will be the last in sorted hash.

My code:

%libs = (
"00000000000","00000000000",
"aaaaaaaaaaa","aaaaaaaaaaa",
"AAAAAAAAAA","AAAAAAAAAA",
"name_iwant_last","name_iwant_last",
"zzzzzzzzzzzzz","zzzzzzzzzzzzz",
"ZZZZZZZZZZZ","ZZZZZZZZZZZ",
"9999999999","9999999999"
);

sub lib_sort {
  #print "cosa ordino ";
  #print $libs{$a};
  #print $libs{$b};
  #print "\n";
  return 1 if (index($libs{$a} , "name_iwant_last") != -1);
 return -1 if $libs{$a} < $libs{$b};
  return 0 if $libs{$a} == $libs{$b};
  return 1 if $libs{$a} > $libs{$b};
}

foreach my $lib (sort lib_sort values %libs) {
    print $lib;
    print "\n";
}

But when i run this code… the print are in random order…

Expected:
aaaaa
AAAAA…
name_iwant_last

resulted:
random!!!

>Solution :

If you add use warnings to your code, then you’ll see a few warnings like this:

Argument "ZZZZZZZZZZZ" isn’t numeric in numeric lt (<) at sort line 20.
Argument "AAAAAAAAAA" isn’t numeric in numeric lt (<) at sort line 20.
Argument "zzzzzzzzzzzzz" isn’t numeric in numeric lt (<) at sort line 20.
Argument "aaaaaaaaaaa" isn’t numeric in numeric lt (<) at sort line 20.
Argument "name_iwant_last" isn’t numeric in numeric lt (<) at sort line 20.

You’re comparing strings, but you’re using the numeric comparison operators (<, ==, >). If you switch to using string comparison operators (lt, eq, gt) then it will work as expected.

And always have use warnings and use strict in your code.