Getting index of an array value

I have two arrays as follows: e = np.array([True, False, True, True]) f = np.array([True, False, False, True]) I want to get the index i where e[i] and f[i] == True. The expected output for the above will be: [0,3] since e[0] == True and f[0] == True; e[3] and f[3] ==True There may be more of such matches, so I need a list of all of the indices which satisfy the above condition. I tried to find the list of matching values by doing this: list(e&f) Out[474]: [True, False, False, True] To get the index, I thought I could use .index(True) of list. But it doesn't work or just gives output as 0. Maybe only giving the first index and not all. Finally, I need the 1 added to each element of output so instead of [0,3] output should be [1,4] but this is easy I can do that if I get the indices,