Array.diff

DESCRIPTION:

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 keeping their order.

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]

---

def array_diff(a, b):
    print(a,b)
    alist=[]
    if a==[]:
        return []
    elif b==[]:
        return a
    for i in range(len(a)):
        if a[i] not in b:
            alist.append(a[i])
    return alist