演示(我期望结果是[3]
):
[1,2] - [1,2,3] => [] # Hmm
[1,2,3] - [1,2] => [3] # I see
a = [1,2].to_set => #<Set: {1, 2}>
b = [1,2,3].to_set => #<Set: {1, 2, 3}>
a - b => #<Set: {}> WTF!
并且:
[1,2,9] - [1,2,3] => [9] # Hmm. Would like [[9],[3]]
如何不考虑输入顺序执行真正的集合差异操作?
附带说明:我需要对两个2000元素数组执行此操作。通常,数组#1的元素数量会少于数组#2,但这并不保证。