Compare Elements in One Array with Two Other Arrays by Position in Numpy

I have a numpy array (a_array) and I need to compare each element with the elements in the same position in b_array and c_array, returning the lower of those two values.

a_array = [5031 5038 5040]
b_array = [5050 5055 5870]
c_array = [5611 5743 5780]

So in the above example:

i. compare 5031 with 5050 and 5611 returning 5050;

ii. compare 5038 with 5055 and 5743 returning 5055;

iii. compare 5040 with 5870 and 5780 returning 5780.

I could use a for loop to do this but is there a vecotorized approach?

>Solution :

If you only care about b_array/c_array, use numpy.minimum:

np.minimum(b_array, c_array)

Output: array([5050, 5055, 5780])

If you want to consider all arrays, you can use np.minimum.reduce:

np.minimum.reduce([a_array, b_array, c_array])

Or hstack and min:

np.vstack([a_array, b_array, c_array]).min(axis=0)

Output: array([5031, 5038, 5040])