Convert Array of Array into string Array in efficient way

Question

I have an array

arr=[["Sumit", "where"], ["where", "are"], ["are", "you"]]

and i want to convert

arr=["Sumit where", "where are", "are you"]

how can i do this in efficient way

Answer 1

arr=[["Sumit", "where"], ["where", "are"], ["are", "you"]]  
v = arr.map { |x| x.join(" ") }  
p v 

Answer 2

try:

arr=[["Sumit", "where"], ["where", "are"], ["are", "you"]]
arr = arr.map {|i| i.join(' ') }