Math::Combinatorics 0.09

Math::Combinatorics is a Perl module that can perform combinations and permutations on lists.

SYNOPSIS

Available as an object oriented API.

use Math::Combinatorics;

my @n = qw(a b c);
my $combinat = Math::Combinatorics->new(count => 2,
data => [@n],
);

print "combinations of 2 from: ".join(" ",@n)."n";
print "------------------------".("--" x scalar(@n))."n";
while(my @combo = $combinat->next_combination){
print join( , @combo)."n";
}

print "n";

print "permutations of 3 from: ".join(" ",@n)."n";
print "------------------------".("--" x scalar(@n))."n";
while(my @permu = $combinat->next_permutation){
print join( , @permu)."n";
}

output:

Or available via exported functions permute, combine, and factorial.

use Math::Combinatorics;

my @n = qw(a b c);
print "combinations of 2 from: ".join(" ",@n)."n";
print "------------------------".("--" x scalar(@n))."n";
print join("n", map { join " ", @$_ } combine(2,@n)),"n";
print "n";
print "permutations of 3 from: ".join(" ",@n)."n";
print "------------------------".("--" x scalar(@n))."n";
print join("n", map { join " ", @$_ } permute(@n)),"n";

Output:

combinations of 2 from: a b c
------------------------------
a b
a c
b c

permutations of 3 from: a b c
------------------------------
a b c
a c b
b a c
b c a
c a b
c b a

Output from both types of calls is the same, but the object-oriented approach consumes much less memory for large sets.