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?

What are you trying to do here? Return a new array from the current array? — Hunter McMillen
– Hunter McMillen, Commented Dec 2, 2011 at 3:23
Remember to restart your server or the new method may not be available yet. — Kevin C
– Kevin C, Commented May 15, 2019 at 19:10

Phrogz · Accepted Answer · 2011-12-02 04:09:17Z

11

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

answered Dec 2, 2011 at 4:09

Phrogz

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Comments

John · Accepted Answer · 2011-12-02 03:24:05Z

9

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}

answered Dec 2, 2011 at 3:24

John

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