Set Theory

Extends Object and Array with nice names for set operations.

See the Set class for a library that doesn't pollute your Objects and Arrays.

gem install set_theory

For the whole library

require 'set_theory'

Or choose the parts you want

require 'set_theory/member_of'
require 'set_theory/difference'
require 'set_theory/intersection'
require 'set_theory/power_set'
require 'set_theory/symmetric_difference'
require 'set_theory/union'

Returns true if the receiving object is found within an array.

1.member_of? [1, 2, 3]     #=> true

Returns an array with the objects of the receiving array that are not in the passed array.

[1, 2, 3].difference [2, 3, 4]    #=> [1]
[2, 3, 4].difference [1, 2, 3]    #=> [4]

Returns an array containing only the objects that are members of both the receiving and passed array.

[1, 2, 3].intersection [2, 3, 4]    #=> [2, 3]

Returns an array with all possible subsets of the receiving array.

[1, 2, 3].power_set    #=> [[], [1], [2], [1, 2], [3], [1, 3], [2, 3], [1, 2, 3]]

Returns an array containing only the objects that are in one of the receiving or passed arrays, but not both.

[1, 2, 3].symmetric_difference [2, 3, 4]    #=> [1, 4]

Returns an array containing all members the receiving and passed arrays.

[1, 2, 3].union [2, 3, 4]    #=> [1, 2, 3, 4]

• rake
• bundler
• gem-release
• rspec

Install dependencies

bundle install

Then run the specs

bundle exec rake

Yes, I know about this patch, but I prefer Object#member_of? and !Object#member_of?.

http://en.wikipedia.org/wiki/Set_theory

http://rosettacode.org/wiki/Power_Set#Ruby

See LICENSE for details.

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