Determine if one array contains all elements of another array

Question

I need to tell if an array contains all of the elements of another array with duplicates.

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


        

Answer 1

If you can't find a method, you can build one using ruby's include? method.

Official documentation: http://www.ruby-doc.org/core-1.9.3/Array.html#method-i-include-3F

Usage:

array = [1, 2, 3, 4]
array.include? 3       #=> true

Then, you can do a loop:

def array_includes_all?( array, comparision_array )
  contains = true
  for i in comparision_array do
    unless array.include? i
      contains = false
    end
  end
  return contains
end

array_includes_all?( [1,2,3,2], [1,2,2] )    #=> true