ruby - Ruby 多维数组

Question

我有一个多维数组：-

arr=  [[ ["paris", "P"], ["spain", "S"] ], [ ["russia", "R"], ["England", "E"] ]... 

1. 我想选择这个数组的一个元素，并想要拆分它的元素，如 ["paris", "P"] 和 ["spain", "S"]

arr.each do |x|
   arr_new<< el1=x.first and el2=x.last
   end

2. 给定此 arr2 的单个元素，我想选择第二个元素并推入 arr2：-

arr2=[]
arr2<<sec_el1=el1.last and sec_el2=el2.last.

什么是正确的红宝石方式？

Answer 1

如果您希望达到的最终结果是抓取P等S

 arr2=[]
 arr=  [["paris", "P"], ["spain", "S"] ], [ ["russia", "R"], ["England", "E"] ]
 arr.flatten.each_with_index{ |e,i| (arr2 << e) if i.odd?}
 puts arr2 #=> ["P", "S", "R", "E"]