数组比较

Question

  

可能重复：
  How to count duplicates in Ruby Arrays
  Ruby: Compare 2 arrays for matches, and count the number of match instances

我开始使用 ruby​​ 语言。假设我有两个数组：

a=["A", "B", "C", "D"]
b=["C", "A", "X", "Y", "F"]

我想计算两个数组中重复元素的数量。为实现这一目标，我提出的想法如下：

nr_of_duplicates = (a- (a - b)).size

有没有更好的方法来实现这一目标？

Answer 1

在Array类中已经定义了一个名为'＆amp; '的方法：

ary & other_ary → new_ary

Set Intersection—Returns a new array containing elements common to the two arrays, with no duplicates.

   [ 1, 1, 3, 5 ] & [ 1, 2, 3 ]   #=> [ 1, 3 ]