How do I perform vector addition in Ruby?

Question

How do I perform vector addition in Ruby so that

[100, 100] + [2, 3] 

yields

[102, 103] 

(instead of joining two arrays)?

Or it can be another operator too, such as

[100, 100] @ [2, 3] 

or

[100, 100] & [2, 3]

Answer 1

See the Vector class:

require "matrix"

x = Vector[100, 100]
y = Vector[2, 3]
print x + y

E:\Home> ruby t.rb
Vector[102, 103]

See vectorops for additional operations on vectors:

… the following operations work like expected

  v1 = Vector[1,1,1,0,0,0]
  v2 = Vector[1,1,1,1,1,1]

  v1[0..3]
  # -> Vector[1,1,1]

  v1 += v2
  # -> v1 == Vector[2,2,2,1,1,1]

  v1[0..3] += v2[0..3]
  # -> v1 == Vector[2,2,2,0,0,0]

  v1 + 2
  # -> Vector[3,3,3,1,1,1]

See also vectorops.

Answer 2

module PixelAddition
  def +(other)
    zip(other).map {|num| num[0]+num[1]}
  end
end

Then you can either create an Array subclass that mixes in the module, or add the behavior to specific arrays like:

class <<an_array
  include PixelAddition
end