Array.diff

题目描述：
# Your goal in this kata is to implement a difference function, which subtracts one list from another and returns the result.
#
# It should remove all values from list a, which are present in list b.
#
# array_diff([1,2],[1]) == [2]
# If a value is present in b, all of its occurrences must be removed from the other:
#
# array_diff([1,2,2,2,3],[2]) == [1,3]


我的解答：

def array_diff(a, b):
    for i in range(len(a)):
        for j in a:
            if j in b:
                a.remove(j)
    return a


网友更加好的方法：

def array_diff(a, b):
    return [x for x in a if x not in set(b)]