How to extend array methods in ruby?

Question

Here is my code:

class Array
    def anotherMap
         self.map {yield}
    end
end

print [1,2,3].anotherMap{|x| x}

I'm expecting to get an output of [1,2,3],but I get [nil,nil,nil]
What's wrong with my code?

Answer 1

class Array
  def another_map(&block)
    map(&block)
  end
end

Answer 2

Your code doesn't yield the value that's yielded to the block you passed to #map. You need to supply a block parameter and call yield with that parameter:

class Array
    def anotherMap
         self.map {|e| yield e }
    end
end

print [1,2,3].anotherMap{|x| x}