Our Mathematical Selection code in Perl.
Mathematical Selection Class File:
package SELECTION;
BEGIN {
require Exporter;
# for the sake of standard
our $VERSION = 2017.10;
# Inherit from exporter to export functions and variables
our @ISA = qw(Exporter);
# Functions and variables to be exported by default
our @EXPORT_OK = qw(possibleWordCombinations);
}
use warnings;
use strict;
our @words;
our $r; # min length of word
my $i;
my @complete_group; # array of references
# simulate an object construct
sub new {
my $self = shift;
my $this = {};
bless $this, $self;
return $this;
}
# point of entry
# returns an array reference of references
sub groupSelection {
shift;
my $arg = shift;
@words = @{$arg};
$r = shift;
@complete_group = ();
$i = 0;
recursiveFillUp([]);
return \@complete_group;
}
# pick elements recursively
sub recursiveFillUp {
my $temp = shift;
my @picked_elements = ();
my $j = $i;
while ($j < scalar @words) {
# dereference 'temp' and save it as an anonymous array reference
$picked_elements[$j] = [@{$temp}];
push @{$picked_elements[$j]}, $words[$j];
# recoil factor
$i = $j if $i >= scalar @words;
# satisfied yet?
if (scalar @{$picked_elements[$j]} == $r) {
push @complete_group, $picked_elements[$j];
} elsif (scalar @{$picked_elements[$j]} < $r) {
recursiveFillUp($picked_elements[$j]);
}
$j++;
}
if (defined $picked_elements[--$j] && scalar @{$picked_elements[$j]} == $r) {
$i++; # keep recoil factor straightened out
}
}
1;Main Class:
#!/usr/bin/perl;
use strict;
use warnings;
use SELECTION;
my @subjects = ("0", "1", "2", "3", "4", "5", "6", "7", "8", "9");
my $r = 9;
# Use the selection module/class
my $pick = SELECTION->new();
# $result receives an array reference of references
my $result = $pick->groupSelection(\@subjects, $r);
print ("[", join(", ", @subjects), "] selection ", $r, ":\n\n");
# for each array reference in a dereferenced '$result'
my $i = 0;
print (++$i, ": ", join(", ", @{$_}), "\n") for @{$result};
print ("\n\nNumber of ways is ", scalar @{$result}, ".");
print "\n\n";Try it out!
Elegance (0.0)
