List::MapList -- map lists through a list of subs, not just one

version 1.121

 $Id: MapList.pm,v 1.6 2005/03/18 21:03:41 rjbs Exp $

Contrived heterogenous transform

 use List::MapList

 my $code = [
   sub { $_ + 1 },
   sub { $_ + 2 },
   sub { $_ + 3 },
   sub { $_ + 4 }
 ];

 my @mapped = maplist( $code, qw(1 2 3 4 5 6 7 8 9));

 # @mapped is qw(2 4 6 8 6 8 10 12 13)

Ultra-secure partial rot13:

 my $rotsome = [
  sub { tr/a-zA-Z/n-za-mN-ZA-M/; $_ },
  sub { tr/a-zA-Z/n-za-mN-ZA-M/; $_ },
  sub { $_ },
 ];

 my $plaintext  = "Too many secrets.";
 my $cyphertext = join '', mapcycle($rotsome, split //, $plaintext);

List::MapList provides methods to map a list through a list of transformations, instead of just one. The transformations are not chained together on each element; only one is used, alternating sequentially.

Here's a contrived example: given the transformations { $_ = 0 } and { $_ = 1 }, the list (1, 2, 3, "Good morning", undef) would become (0, 1, 0, 1, 0) or, without cycling, (0, 1).;

(I use this code to process a part number in which each digit maps to a set of product attributes.)

maplist($coderefs, LIST)

This routine acts much like a normal map, but uses the list of code references in $coderefs in parallel with the list members. First first code reference is used for the first list member, the next for the second, and so on. Once the last code reference has been used, all further elements will be mapped to ().

mapcycle($coderefs, LIST)

This routine is identical to maplist, but will cycle through the passed coderefs over and over as needed.

...nothing?

Ricardo SIGNES <rjbs@iqep.com>

This code is Copyright 2004-2006, Ricardo SIGNES. It is free software, available under the same terms as Perl itself.