numpy.power() in Python

Last Updated : 29 Nov, 2018
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numpy.power(arr1, arr2, out = None, where = True, casting = 'same_kind', order = 'K', dtype = None) : Array element from first array is raised to the power of element from second element(all happens element-wise). Both arr1 and arr2 must have same shape and each element in arr1 must be raised to corresponding +ve value from arr2; otherwise it will raise a ValueError. Parameters : 
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.
Return : 
An array with elements of arr1 raised to exponents in arr2
  Code 1 : arr1 raised to arr2 Python 
# 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)
Output : 
arr1         :  [2, 2, 2, 2, 2]
arr2         :  [2, 3, 4, 5, 6]

Output array :  [ 4  8 16 32 64]
  Code 2 : elements of arr1 raised to exponent 2 Python 
# 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)
Output : 
arr1         :  [0 1 2 3 4 5 6 7]

Output array :  [ 0  1  4  9 16 25 36 49]
  Code 3 : Error if arr2 has -ve elements Python 
# 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)
Output : 
arr1         :  [2, 2, 2, 2, 2]
arr2         :  [2, -3, 4, -5, 6]
ValueError: Integers to negative integer powers are not allowed.
References : https://docs.scipy.org/doc/numpy-1.13.0/reference/generated/numpy.power.html#numpy.power .

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