は、私は2次元配列を持っている

Question

2次元配列の（最初の1を除く）の要素を使用して3Dの配列を作成します

[["abc",["def"]],["ghi",["jkl","mno"]]] 

Answer 1

arr = [["abc","def"],["ghi","jkl","mno"]] 

arr.map { |first, *rest| [first, rest] } 
    #=> [["abc", ["def"]], ["ghi", ["jkl", "mno"]]]