8.5.常量

import numpy as np

Windows 10
Python 3.8.8 @ MSC v.1928 64 bit (AMD64)
Latest build date 2021.03.09
numpy version:  1.20.1

NumPy 定义了几个常量（都是IEEE 754 浮点表示）：

| Attributes         |Values                 |Annotations           
| :--------------    |:------------------    |:-------------------  
| np.inf             |inf                    |正无穷大              
| np.Inf             |inf                    |alias of inf          
| np.infty           |inf                    |alias of inf          
| np.Infinity        |inf                    |alias of inf          
| np.PINF            |inf                    |alias of inf          
| np.NINF            |-inf                   |负无穷大              
| np.nan             |nan                    |非数字: Not a Number     
| np.NAN             |nan                    |alias of nan          
| np.NaN             |nan                    |alias of nan          
| np.NZERO           |-0.0                   |负零                    
| np.PZERO           |0.0                    |正零                    
| np.e               |2.718281828459045      |自然底数/纳皮尔常数    
| np.euler_gamma     |0.5772156649015329     |欧拉常数              
| np.pi              |3.141592653589793      |圆周率                   
| np.newaxis         |None                   |新轴/None别名