Warning: Undefined array key "action" in /home/bakers/html/entryreply.php on line 5

Warning: Undefined variable $output in /home/bakers/html/entryreply.php on line 50

Warning: Undefined array key "EntrySubject" in /home/bakers/html/entryreply.php on line 51

Warning: Undefined variable $logintext in /home/bakers/html/entryreply.php on line 97

Warning: Undefined variable $reply_name in /home/bakers/html/entryreply.php on line 103

Warning: Undefined variable $reply_email in /home/bakers/html/entryreply.php on line 104
Perturb.org - interesting technology related things from around the internet

Perl: Natural Sort

I have a array with a bunch of names like vlan-1, vlan100, vlan34 which do not sort appropriately using Perl's standard sort() function. Sort::Naturally to the rescue! I didn't want to install an entire module for one sort operation, and require a dependency, so I ripped out just the natural sort function and included that in my script.

sub nsort {
    my($cmp, $lc);
    return @_ if @_ < 2;   # Just to be CLEVER.

    my($x, $i);  # scratch vars

    map
        $_->[0],

    sort {
        # Uses $i as the index variable, $x as the result.
        $x = 0;
        $i = 1;

        while($i < @$a and $i < @$b) {
            last if ($x = ($a->[$i] cmp $b->[$i])); # lexicographic
            ++$i;

            last if ($x = ($a->[$i] <=> $b->[$i])); # numeric
            ++$i;
        }

        $x || (@$a <=> @$b) || ($a->[0] cmp $b->[0]);
    }

    map {
        my @bit = ($x = defined($_) ? $_ : '');

        if($x =~ m/^[+-]?(?=\d|\.\d)\d*(?:\.\d*)?(?:[Ee](?:[+-]?\d+))?\z/s) {
            # It's entirely purely numeric, so treat it specially:
            push @bit, '', $x;
        } else {
            # Consume the string.
            while(length $x) {
                push @bit, ($x =~ s/^(\D+)//s) ? lc($1) : '';
                push @bit, ($x =~ s/^(\d+)//s) ?    $1  :  0;
            }
        }

        \@bit;
    }
    @_;
}

This is a slightly more portable version rather than maintaining the Sort::Naturally dependency.

See also: Natural Sort Part Deux



Note: Replies will be formatted with PHP Markdown Extra syntax.

Name: Email (Not Required):
 
Logged IP: 3.238.95.208
To prevent spam please submit by clicking the kitten: