Numpy中的数学函数

1. np,around(a)：
   对输入值进行4舍6入的处理，5进行特殊处理。5舍入为本身距离最小的偶数值。例如 np,around[(1.5)]=2,但是np,around[(2.5)]=2同样是正确的。

import numpy as np
print("np.around(1.5):",np.around(1.5))
print("np.around(2.5):",np.around(2.5))


Run:
D:\python\python.exe C:/Users/ThinkPad/PycharmProjects/pythonProject/HelloWorld.py 
np.around(1.5): 2.0
np.around(2.5): 2.0

Process finished with exit code 0

2. np.around(a,decimals=b)：
   将一个小数4舍6入、5特殊处理到规定小数位数，当b>0时，精确到小数点后b位；当b<0时，精确到小数点前b位

import numpy as np
print("np.around(2.6,decimals=1):",np.around(2.6,decimals=1))
print("np.around(2.6,decimals=-1):",np.around(2.6,decimals=-1))

Run:

D:\python\python.exe C:/Users/ThinkPad/PycharmProjects/pythonProject/HelloWorld.py 
np.around(2.6,decimals=1): 2.6
np.around(2.6,decimals=-1): 0.0

Process finished with exit code 0

4. np.floor(a)：
   返回不大于输入参数的最大整数，即i<=x

import numpy as np
print("np.floor(2.6):",np.floor(2.6))

Run:
D:\python\python.exe C:/Users/ThinkPad/PycharmProjects/pythonProject/HelloWorld.py 
np.floor(2.6): 2.0

Process finished with exit code 0

6. np.ceil(a):
   返回不小于输入参数的最大整数，即i>=x

import numpy as np
print("np.ceil(2.6):",np.ceil(2.6))

Run:
D:\python\python.exe C:/Users/ThinkPad/PycharmProjects/pythonProject/HelloWorld.py 
np.ceil(2.6): 3.0

Process finished with exit code 0