Check whether all elements of a NumPy array match a condition

Question

For a given 2 dimentional arrays such as below, i need to check if all the elements are less than 0.2.

a = np.array([[0.26002, 0.13918, 0.6008 ],
              [0.2997 , 0.28646, 0.41384],
              [0.41614, 0.36464, 0.21922]])

Here is my code, based on this question.

 res = abs(a<0.2)
 all(i==True for i in res)

But the code complains with

ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

I did not downvote either the question or the answer here. But it would be great if you could acknowledge my comment above. — cs95, Mar 31 '19 at 20:31
@coldspeed yes, it works well. if you write it as an answer, i will approve it. Thanks a lot. — Jeff, Mar 31 '19 at 20:34
Btw abs(boolean condition) makes no sense. I suppose you meant abs(array) < 0.2 — cs95, Mar 31 '19 at 20:37

score 11 · Accepted Answer · answered Mar 31 '19 at 20:36

11

The key is to use np.all here:

(np.abs(a) < 0.2).all()
# False

(a < 1).all()
# True

answered Mar 31 '19 at 20:36

cs95

1 Answers1