NumPy Products

Products

To find the product of the elements in an array, use the prod() function.

Find the product of the elements of this array:

import numpy as np

arr = np.array([1, 2, 3, 4])

x = np.prod(arr)

print(x)

Returns: 24 because 1*2*3*4 = 24

Find the product of the elements of two arrays:

import numpy as np

arr1 = np.array([1, 2, 3, 4])
arr2 = np.array([5, 6, 7, 8])

x = np.prod([arr1, arr2])

print(x)

Returns: 40320 because 1*2*3*4*5*6*7*8 = 40320

If you specify axis=1, NumPy will return the product of each array.

Perform summation in the following array over 1st axis:

import numpy as np

arr1 = np.array([1, 2, 3, 4])
arr2 = np.array([5, 6, 7, 8])

newarr = np.prod([arr1, arr2], axis=1)

print(newarr)

Returns: [24 1680]

Cummulative product means taking the product partially.

E.g. The partial product of [1, 2, 3, 4] is [1, 1*2, 1*2*3, 1*2*3*4] = [1, 2, 6, 24]

Perfom partial sum with the cumprod() function.

Take cummulative product of all elements for following array:

import numpy as np

arr = np.array([5, 6, 7, 8])

newarr = np.cumprod(arr)

print(newarr)

Returns: [5 30 210 1680]