numpy.isinf() in Python

Difficulty Level : Basic
Last Updated : 23 Oct, 2020

The numpy.isinf() function tests element-wise whether it is +ve or -ve infinity or not return the result as a boolean array.

Syntax: numpy.isinf(array [, out])

Parameters :

array : [array_like]Input array or object whose 
         elements, we need to test for  infinity
out   : [ndarray, optional]Output array placed 
        with result. Its type is preserved and
        it  must be of the right shape to hold 
         the output.

Return :

boolean array containing the result. For scalar 
input, the result is a new boolean with value
True if the input is positive or negative infinity; 
otherwise the value is False. For array input, the 
result is a boolean array with the same shape as 
the input and the values are True where the 
corresponding element of the input is positive
or negative infinity; elsewhere the values are False.

Code 1 :

# Python Program illustrating 
# numpy.isinf() method 
   
import numpy as geek  
  
print("Finite : ", geek.isinf(1), "\n") 
  
print("Finite : ", geek.isinf(0), "\n") 
  
# not a number 
print("Finite : ", geek.isinf(geek.nan), "\n") 
  
#  infinity 
print("Finite : ", geek.isinf(geek.inf), "\n") 
  
print("Finite : ", geek.isinf(geek.NINF), "\n")  
  
x = geek.array([-geek.inf, 0., geek.inf]) 
y = geek.array([2, 2, 2]) 
print("Checking for infinity : ", geek.isinf(x, y))  

Output :

Finite :  False 

Finite :  False 

Finite :  False 

Finite :  True 

Finite :  True 

Checking for infinity :  [1 0 1]

Code 2 :

# Python Program illustrating 
# numpy.isinf() method 
    
import numpy as geek  
   
# Returns True/False value for each element  
b = geek.arange(8).reshape(2, 4) 
                 
print("\n",b) 
print("\nIs Infifnity : \n", geek.isinf(b)) 
  
# geek.inf  : Positive Infinity 
# geek.NINF : negative Infinity 
b = [[geek.inf],  
     [geek.NINF]] 
print("\nIs Infifnity : \n", geek.isinf(b)) 

Output :


 [[0 1 2 3]
 [4 5 6 7]]

Is Infifnity : 
 [[False False False False]
 [False False False False]]

Is Infifnity : 
 [[ True]
 [ True]]

References :
https://docs.scipy.org/doc/numpy-dev/reference/generated/numpy.isinf.html#numpy.isinf

Note :
These codes won’t run on online-ID. Please run them on your systems to explore the working.
.
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