ruby-帮助需要将数组转换为特定类型的数组，将键复制为列表中的[key，value]

Question

I want to convert and array into a specific type of array of arrays.

array = ["Project", "Publication"]

into

array_of_arrays =[["Project", "Project"], ["Publication", "Publication"] ]

The array is not just limited to size two. Its a growing list , so looking for some function to convert it to array_of_arrays.

Appreciate any help.

Answer 1

def replicate(arr, n)
  arr.map { |e| [e]*n }
end

replicate(["Project", "Publication"], 2)
  #=> [["Project", "Project"], ["Publication", "Publication"]]
replicate(["Project", "Publication"], 3)
  #=> [["Project", "Project", "Project"], ["Publication", "Publication", "Publication"]]
replicate([["ProjectA", "ProjectB"], "Publication"], 2)
  #=> [[["ProjectA", "ProjectB"], ["ProjectA", "ProjectB"]], ["Publication", "Publication"]

Answer 2

This is something map can handle quite easily.

a = ["Project", "Publication"]
a.map{|x| [x,x]}
#=> [["Project", "Project"], ["Publication", "Publication"]]