Finding instances similar in two lists with the same shape

Question

I am working with a timeseries data. Let's say I have two lists of equal shape and I need to find instances where both lists have numbers greater than zero at the same position.

To break it down

A = [1,0,2,0,4,6,0,5]
B = [0,0,5,6,7,5,0,2]

We can see that in four positions, both lists have numbers greater than 0. There are other instances , but I am sure if I can get a simple code, all it needs is adjusting the signs and I can also utilize in a larger scale.

I have tried

len([1 for i in A if i > 0 and 1 for i in B if i > 0 ])

But I think the answer it's giving me is a product of both instances instead.

Answer 1

Since you have a numpy tag:

A = np.array([1,0,2,0,4,6,0,5])
B = np.array([0,0,5,6,7,5,0,2])

mask = ((A>0)&(B>0))
# array([False, False,  True, False,  True,  True, False,  True])

mask.sum()
# 4

A[mask]
# array([2, 4, 6, 5])

B[mask]
# array([5, 7, 5, 2])

In pure python (can be generalized to any number of lists):

A = [1,0,2,0,4,6,0,5]
B = [0,0,5,6,7,5,0,2]

mask = [all(e>0 for e in x) for x in zip(A, B)]

# [False, False, True, False, True, True, False, True]