Filter a list based on another list with multiple choices of elements

Suppose I have a list a=[1, 3, 4, 5, 7] and another list b=[0,0,1,1,3].

Now I want to filter a to make a new list where the corresponding position in b is 0 or 3. If I only want b to be 0, it’s simply a = a[b==0], but now it’s filtering based on a subset.
What I did is :

subset = [0, 1]
a = a[b in subset]

which is not correct and the error goes:ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

I wonder what is the correct way to do so. Thanks!

>Solution :

If I understand your question right then you’re looking for np.isin:

a = np.array([1, 3, 4, 5, 7])
b = np.array([0, 0, 1, 1, 3])

print(a[np.isin(b, [0, 3])])

Prints:

[1 3 7]