Is there a quick simple way to multiply multiple columns from a numpy matrix? I'm using the code I show bellow but I was wondering if numpy offers a direct method.
x = np.array([[1,2,3,4],[5,6,7,8],[9,10,11,12]])
temp = np.ones(3)
for ind in [0,3]:
temp *= x[:,ind]
print(temp)
array([ 4., 40., 108.])
Using numpy indexing and numpy.prod. idx can be any number of columns from your array:
>>> idx = [0, 3]
>>> np.prod(x[:, idx], axis=1)
array([ 4, 40, 108])
Also equivalent:
x[:, idx].prod(1)
You can multiply the columns since numpy multiplication is element-wise:
x[:, 0] * x[:, 3]
returns
array([ 4, 40, 108])
