NAME

Sort::Key::Natural - fast natural sorting

SYNOPSIS

    use Sort::Key::Natural 'natkeysort';

    my @data = qw(foo1 foo23 foo6 bar12 bar1
                  foo bar2 bar-45 b-a-r-45);

    my @sorted = natkeysort { $_ } @data;

    print "@sorted\n";
    # prints:
    #   b-a-r-45 bar1 bar2 bar12 bar-45 foo foo1 foo6 foo23

DESCRIPTION

This module extends the Sort::Key family of modules to support natural sorting.

Under natural sorting, strings are splitted in word and number boundaries, and the resulting substrings are compared as follows:

• numeric substrings are compared numerically

• alphabetic substrings are compared lexically

• numeric substrings come always before alphabetic substrings

Spaces, symbols and non-printable characters are only considered for splitting the string into its parts but not for sorting. For instance foo-bar-42 is broken in three substrings foo, bar and 42 and after that the dashes are ignored.

Once this module is loaded, the new type natural (or nat) will be available from Sort::Key::Maker. For instance:

  use Sort::Key::Natural;
  use Sort::Key::Maker i_rnat_keysort => qw(integer -natural);

creates a multikey sorter i_rnat_keysort accepting two keys, the first to be compared as an integer and the second in natural descending order.

FUNCTIONS

the functions that can be imported from this module are:

natkeysort { CALC_KEY($_) } @data;

returns the elements on @array naturally sorted by the key resulting from applying CALC_KEY to them.

rnatkeysort { CALC_KEY($_) } @data;

is similar to natkeysort but sorting the elements on descending order.

natkeysort_inplace { CALC_KEY($_) } @data;

rnatkeysort_inplace { CALC_KEY($_) } @data;

these functions are similar to natsortkey and rnatsortkey but sort the array @data in place.

mkkey_natural $key

transforms key $key in a way that when sorted with Sort::Key keysort results in a natural sort. If the argument $key is not provided it defaults to $_

SEE ALSO

Sort::Key, Sort::Key::Maker.

Other module providing similar functionality is Sort::Natural.

COPYRIGHT AND LICENSE

Copyright (C) 2006 by Salvador Fandiño, <sfandino@yahoo.com>.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.4 or, at your option, any later version of Perl 5 you may have available.