List::Group - Group a list of data structures to your specifications.

List-Group documentation Contained in the List-Group distribution.

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NAME

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List::Group - Group a list of data structures to your specifications.

SYNOPSIS

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  use List::Group qw[group];
  my @list  = qw[cat dog cow rat];
  my @group = group @list, cols => 2;

  foreach my $row ( @group ) {
    print "@{$row}\n";
  }

DESCRIPTION

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A simple module that currently allows you to group a list by columns or rows.

Functions

group listref, args
  my @table = group \@list, cols => 2;

This function returns a list-of-lists containing the elements of listref passed as the first argument. The remaining arguments detail how to group the elements. Available groupings are cols, and rows. Each of these groupings accept a single digit as a value, the number of cols or rows to create.

The following is what @table would look like from the previous example.

  my @list  = qw[cat dog mouse rat];
  my @table = group \@list, cols => 2;

  print Dumper \@table;
  __END__

  $VAR1 = [
    [ 'cat', 'dog' ],
    [ 'mouse', 'rat' ]
  ];

AUTHOR

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Casey West, <casey@geeknest.com>.

COPYRIGHT

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  Copyright (c) 2004 Casey West.  All rights reserved.
  This module is free software; you can redistribute it and/or modify it
  under the same terms as Perl itself.
List-Group documentation Contained in the List-Group distribution. 
package List::Group;
# $Id: Group.pm,v 1.3 2004/02/24 23:52:58 cwest Exp $
use strict;
use base qw[Exporter];
use Carp;
use POSIX qw[ceil];
use Storable qw[dclone];

use vars qw[$VERSION @EXPORT_OK %EXPORT_TAGS];
$VERSION = (qw$Revision: 1.3 $)[1];
@EXPORT_OK = ( qw[group] );
%EXPORT_TAGS = ( all => [ @EXPORT_OK ] );


sub group($$$;) {
  my ($list, $group_by, $number) = @_;
  croak "First argument to __PACKAGE__\::group() was not a list ref!"
    unless ref($list) eq 'ARRAY';
  croak "Number of $group_by passed to __PACKAGE__\::group() was not a digit"
    if $number =~ /\D/ && grep $group_by, qw[cols rows];
  my $grouping;
  $grouping = _group_by_cols(dclone($list), $number) if $group_by eq 'cols';
  $grouping = _group_by_rows(dclone($list), $number) if $group_by eq 'rows';
  return wantarray ? @{$grouping} : $grouping if $grouping;
  croak "Unrecognized group by argument '$group_by' to __PACKAGE__\::group()";
}


sub _group_by_cols($$;) {
  my ($list, $number) = @_;
  my $grouping = [];
  push @{$grouping}, [ splice @{$list}, 0, $number ]
    while @{$list};
  return $grouping;
}

sub _group_by_rows($$;) {
  my ($list, $number) = @_;
  return _group_by_cols($list, ceil @{$list}/$number);
}

1;

__END__