numpy.nansum () in Python



numpy.nansum() is used when we want to calculate the sum of array elements along a given axis, treating Not Numbers (NaNs) as zero.

Syntax: numpy.nansum (arr, axis = None, dtype = None, out = None, keepdims = `no value`)

Parameters:
arr: [array_like] Array containing numbers whose sum is desired. If arr is not an array, a conversion is attempted.
axis: Axis or axes along which the sum is computed. The default is to compute the sum of the flattened array.
dtype: The type of the returned array and of the accumulator in which the elements are summed. By default, the dtype of arr is used.
out: [ndarray, optional] A location into which the result is stored.
 – & gt ; If provided, it must have a shape that the inputs broadcast to.
 – & gt; If not provided or None, a freshly-allocated array is returned.
keepdims: bool, optional
 – & gt; If this is set to True, the axes which are reduced are left in the result as dimensions with size one. With this option, the result will broadcast correctly against the original arr.
 – & gt; If the value is anything but the default, then keepdims will be passed through to the mean or sum methods of sub-classes of ndarray.
 – & gt; If the sub-classes methods does not implement keepdims any exceptions will be raised.

Return: A new array holding the result is returned unless out is specified, in which it is returned … The result has the same size as arr, and the same shape as arr, if axis is not None or arr, is a 1-d array.

Code # 1: Work

# Python program explaining
# numpy.nansum () function

 

import numpy as geek

in_num = 10

 

print ( " Input number: " , in_num)

 

out_sum = geek.nansum (in_num) 

< code class = "functions"> print ( "sum of array element:" , out_sum) 

Output:

 Input number: 10 sum of array element: 10 

Code # 2:

# Python program explaining
# numpy.nansum function

  

import numpy as geek

 

in_arr = geek.array ([[ 2 , 2 , 2 ], [ 2 , 2 , geek.nan]])

  

print ( "Input array:" , in_arr) 

 

out_sum = geek.nansum (in_arr) 

print ( "sum of array elements:" , out_sum) 

Output:

 Input array: [[2. 2. 2.] [2 . 2. nan]] sum of array elements: 10.0 

Code # 3:

# Program Python, explaining
# numpy.nansum function

 

import numpy as geek

  

in_arr = geek.array ([[ 2 , 2 , 2 ], [ 2 , 2 , geek.nan]])

 

print ( "Input array:" , in_arr) 

 

out_sum = geek.nansum (in_arr, axis = 1

print ( "sum of array elements taking axis 1: " , out_sum) 

Output:

 Input array: [[2. 2. 2.] [2. 2. nan]] sum of array elements taking axis 1: [6. 4.] 

Note: if both positive and negative infinity are present, the sum will not be a number (NaN). If one of positive and negative infinity is present, the sum will be positive or negative infinity, which is present.

Code # 4:

# Python program explaining
# numpy.nansum () function

 

import numpy as geek

 

in_arr1 = geek.array ([ 2 , - 5 , geek.nan, geek.inf])

in_arr2 = geek.array ([ 1 , 4 , geek.inf, - geek.inf])

  

print ( "1st array elements:" , in_arr1) 

print ( "2nd array elements:" , in_arr2) 

 

out_sum1 = geek.nansum (in_arr1) 

out_sum2 = geek.nansum (in_arr2 )

 

print ( " sum of 1st array elements: " , out_sum1) 

print ( "sum of 2nd array elements:" , out_sum2) 

Output:

 1st array elements: [2. -5. nan inf] 2nd array elements: [1. 4.inf -inf] sum of 1st array elements: inf sum of 2nd array elements: nan