- github.com/postmodern/combinatorics
- github.com/postmodern/combinatorics/issues
- Postmodern (postmodern.mod3 at gmail.com)
A collection of modules and methods for performing Combinatoric calculations.
- Adds
powersetto {Array} and {Set}. - Added {Range#&}, {Range#upto} and {Range#downto}.
- Adds Haskell/Python style list comprehensions via {Array#comprehension}.
Power-set of an {Array}:
require 'combinatorics/power_set'
[1,2,3,4].powerset
# => [[],
[4],
[3],
[3, 4],
[2],
[2, 4],
[2, 3],
[2, 3, 4],
[1],
[1, 4],
[1, 3],
[1, 3, 4],
[1, 2],
[1, 2, 4],
[1, 2, 3],
[1, 2, 3, 4]]
Power-set of a {Set}:
Set['ab', 'cd', 'ef'].powerset
# => [#<Set: {}>,
#<Set: {"ef"}>,
#<Set: {"cd"}>,
#<Set: {"cd", "ef"}>,
#<Set: {"ab"}>,
#<Set: {"ab", "ef"}>,
#<Set: {"ab", "cd"}>,
#<Set: {"ab", "cd", "ef"}>]
Find the intersecting sub-range between two ranges:
(1..50) & (20..100)
# => (20..50)
Enumerate over every sub-range between two ranges:
(1..5).upto(2..10).to_a
# => [1..5, 1..6, 1..7, 1..8, 1..9, 1..10,
2..5, 2..6, 2..7, 2..8, 2..9, 2..10]
List comprehensions:
require 'combinatorics/list_comprehension'
[(0..10).step(2),('a'..'c')].comprehension.to_a
# => [[0, "a"],
[0, "b"],
[0, "c"],
[2, "a"],
[2, "b"],
[2, "c"],
[4, "a"],
[4, "b"],
[4, "c"],
[6, "a"],
[6, "b"],
[6, "c"],
[8, "a"],
[8, "b"],
[8, "c"],
[10, "a"],
[10, "b"],
[10, "c"]]
- ruby >= 1.8.7
$ sudo gem install combinatorics
Copyright (c) 2010 Hal Brodigan
See {file:LICENSE.txt} for license information.