sum of numpy array code example

Example 1: python get a vector of row sums from an array

# Basic syntax:
np.sum(your_array, axis=1).tolist()
# Where axis=1 sums across rows and axis=0 sums across columns

# Example usage:
import numpy as np
your_array = np.array([range(0,4),range(3,7),range(1,5),range(2,6)])
print(your_array)
--> [[0 1 2 3]
 	 [3 4 5 6]
     [1 2 3 4]
     [2 3 4 5]]

np.sum(your_array, axis=0).tolist() # Return column sums
--> [6, 10, 14, 18]
np.sum(your_array, axis=1).tolist() # Return row sums
--> [6, 18, 10, 14]

Example 2: sum axis in python

import numpy as np

array1 = np.array(
    [[1, 2],
     [3, 4],
     [5, 6]])

total_0_axis = np.sum(array1, axis=0)
print(f'Sum of elements at 0-axis is {total_0_axis}')

total_1_axis = np.sum(array1, axis=1)
print(f'Sum of elements at 1-axis is {total_1_axis}')
Output:


Sum of elements at 0-axis is [ 9 12]
Sum of elements at 1-axis is [ 3  7 11]

Example 3: sum along axis python

import numpy as np
matrix=np.ones((10,10))
print(matrix.sum(axis=0))
print(matrix.sum(axis=1))

Example 4: sum of a numpy array

>>> np.sum([0.5, 1.5])
2.0
>>> np.sum([0.5, 0.7, 0.2, 1.5], dtype=np.int32)
1
>>> np.sum([[0, 1], [0, 5]])
6
>>> np.sum([[0, 1], [0, 5]], axis=0)
array([0, 6])
>>> np.sum([[0, 1], [0, 5]], axis=1)
array([1, 5])
>>> np.sum([[0, 1], [np.nan, 5]], where=[False, True], axis=1)
array([1., 5.])

Example 5: python sum of list axes

>>> np.sum([[0, 1], [0, 5]])
6
>>> np.sum([[0, 1], [0, 5]], axis=0)
array([0, 6])
>>> np.sum([[0, 1], [0, 5]], axis=1)
array([1, 5])

Example 6: python np.sum

npsum = np.sum(array)