gistfile1.txt

Add a method named add_index to the Array class. The method should take the index value of an element's position and add it to the String in the same position.

Hint: the each_with_index method should help you solve this problem. Try to find the each_with_index method yourself in Ruby Docs, and learn how it's used.

2.0.0-p353 :001 > class Array
2.0.0-p353 :002?>   def add_index
2.0.0-p353 :003?>     self.each_with_index do |value, position|
2.0.0-p353 :004 >         puts "#{position} is #{value}"
2.0.0-p353 :005?>       end
2.0.0-p353 :006?>     end
2.0.0-p353 :007?>   end
 => nil 
2.0.0-p353 :008 > [1,2,3].add_index
0 is 1
1 is 2
2 is 3
 => [1, 2, 3] 
2.0.0-p353 :009 > [1,2,3].add_index.join(" ")
0 is 1
1 is 2
2 is 3
 => "1 2 3" 

result = []
each_with_index { |n, index| result << "#{n} is #{index}" }
result

which you'd actually write:

each_with_index.map { |n, index| "#{n} is #{index}" }