Python中的 numpy.isposinf()

numpy.isposinf()函数逐元素测试它是否为正无穷大，并将结果作为布尔数组返回。

句法 ：

numpy.isposinf(array, y = None)

参数：

array : [array_like]Input array or object whose elements, we need to test for infinity.
y     : [array_like]A boolean array with the same shape and type as x to store the result.

返回：

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.

代码 1：

Python

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

输出 ：

Positive :  False 

Positive :  False 

Positive :  False 

Positive :  True 

Positive :  False 

Checking for positivity :  [0 0 1]

代码 2：

Python

# Python Program illustrating
# numpy.isposinf() method
   
import numpy as geek
  
# Returns True/False value for each element
b = geek.arange(18).reshape(3, 6)
                
print("\n",b)
print("\nIs Positive Infinity : \n", geek.isposinf(b))
 
# geek.inf means Infinity
# geek.NINF means negative infinity
b = [[geek.inf],
     [geek.NINF]]
print("\nIs Positive Infinity : \n", geek.isposinf(b))

输出 ：

[[ 0  1  2  3  4  5]
 [ 6  7  8  9 10 11]
 [12 13 14 15 16 17]]

Is Positive Infinity : 
 [[False False False False False False]
 [False False False False False False]
 [False False False False False False]]

Is Positive Infinity : 
 [[ True]
 [False]]

参考 ：
https://docs.scipy.org/doc/numpy-dev/reference/generated/numpy.isposinf.html#numpy.isposinf

笔记 ：
这些代码不会在在线 IDE 上运行。因此，请在您的系统上运行它们以探索其工作原理。