Numpy logical and between two array with filter

Question

x = [1,1,1,1]
y = [1,1,1,1]
np.logical_and(x == 1, y == 1)

Output: False

I am expecting an output of [True, True, True, True]. How to achieve this?

MSeifert · Accepted Answer · 2019-11-12 21:33:32Z

1

In your example x and y are lists not arrays. When you compare a list with an integer using == you'll always get False:

>>> [1,1,1,1] == 1
False
>>> [1,1,1,1] == 1
False
>>> np.logical_and(False, False)
False

You have to convert them to arrays, because arrays implement == to work element-wise:

>>> x = np.array([1, 1, 1, 1])
>>> x == 1
array([ True,  True,  True,  True])

>>> x = np.array([1, 1, 1, 1])
>>> y = np.array([1, 1, 1, 1])
>>> np.logical_and(x == 1, y == 1)
array([ True,  True,  True,  True])

edited Nov 12, 2019 at 21:33

answered Nov 12, 2019 at 21:28

MSeifert

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