Get last value from array of arrays

Question

arr = [[a,1], [b,3], [c,2]]

如何将上面的数组转换为以下数组：

[1,3,2]

Answer 1

Use map & last :

arr.map(&:last)  #=> [1,3,2]

this is equivalent to the longer

arr.map { |o| o.last }

Answer 2

只需简单地arr.map(&:last) 。

Answer 3

Another, more explicit way to perform this operation is with Array#collect:

array = [['a', 1], ['b', 3], ['c', 2]]
array.collect { |subarray| subarray.last }

It just depends on what semantics you need to represent what you're doing.

Answer 4

如果每个元素都是一个2元素数组，那么就像这样

arr.map{|x,y| y}