Python numpy.power()用法及代码示例

numpy.power(arr1，arr2，out = None，where = True，cast ='same_kind'，order ='K'，dtype = None)：
来自第一个数组的数组元素被提升为来自第二个元素的元素的幂(所有情况都逐个元素发生)。 arr1和arr2必须具有相同的形状，并且arr1中的每个元素都必须从arr2升高到相应的+ ve值；否则将引发ValueError。
参数：

arr1     : [array_like]Input array or object which works as base.
arr2     : [array_like]Input array or object which works as exponent. 
out      : [ndarray, optional]Output array with same dimensions as Input array, 
           placed with result.
**kwargs : Allows you to pass keyword variable length of argument to a function. 
           It is used when we want to handle named argument in a function.
where    : [array_like, optional]True value means to calculate the universal 
           functions(ufunc) at that position, False value means to leave the 
           value in the output alone.

返回：

An array with elements of arr1 raised to exponents in arr2

代码1：将arr1提升为arr2

# Python program explaining 
# power() function 
import numpy as np 
  
# input_array 
arr1 = [2, 2, 2, 2, 2] 
arr2 = [2, 3, 4, 5, 6] 
print ("arr1         : ", arr1) 
print ("arr1         : ", arr2) 
  
# output_array 
out = np.power(arr1, arr2) 
print ("\nOutput array : ", out)

输出：

arr1         :  [2, 2, 2, 2, 2]
arr2         :  [2, 3, 4, 5, 6]

Output array :  [ 4  8 16 32 64]

代码2：将arr1的元素提高到指数2

# Python program explaining 
# power() function 
import numpy as np 
  
# input_array 
arr1 = np.arange(8) 
exponent = 2
print ("arr1         : ", arr1) 
  
# output_array 
out = np.power(arr1, exponent) 
print ("\nOutput array : ", out)

输出：

arr1         :  [0 1 2 3 4 5 6 7]

Output array :  [ 0  1  4  9 16 25 36 49]

代码3：如果arr2具有-ve元素，则错误

# Python program explaining 
# power() function 
import numpy as np 
  
# input_array 
arr1 = [2, 2, 2, 2, 2] 
arr2 = [2, -3, 4, -5, 6] 
print ("arr1         : ", arr1) 
print ("arr2         : ", arr2) 
  
# output_array 
out = np.power(arr1, arr2) 
print ("\nOutput array : ", out)

输出：

arr1         :  [2, 2, 2, 2, 2]
arr2         :  [2, -3, 4, -5, 6]
ValueError: Integers to negative integer powers are not allowed.

参考文献：
https://docs.scipy.org/doc/numpy-1.13.0/reference/generated/numpy.power.html#numpy.power
。