如何从Ruby中的最后一个元素迭代数组

Question

  

可能重复：
  How to iterate through an array starting from the last element? (Ruby)

我试图反过来迭代列表，但我无法弄明白。

这是我的代码：

#!/usr/bin/ruby
presidents = ["Ford", "Carter", "Reagan", "Bush1", "Clinton", "Bush2"]

for ss in -presidents.length...0
    print  ": ", presidents[ss], "\n";
end

Answer 1

使用reverse_each

presidents = ["Ford", "Carter", "Reagan", "Bush1", "Clinton", "Bush2"]
presidents.reverse_each { |president| p president }

Answer 2

presidents = ["Ford", "Carter", "Reagan", "Bush1", "Clinton", "Bush2"]

presidents.reverse.each do |president|
  puts president
end

Answer 3

这是另一种方式

(presidents.length-1).step(0,-1) {|i| p presidents[i]}