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Combinatorics

Description

A collection of modules and methods for performing Combinatoric calculations.

Features

  • Adds powerset to {Array} and {Set}.
  • Adds Haskell/Python style list comprehensions via {Array#comprehension}.

Examples

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"}>]

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"]]

Install

$ sudo gem install combinatorics

License

See {file:LICENSE.txt} for license information.

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