sum() python numpy 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 along axis python

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