NumPy | Get the Powers of Array Values Element-Wise

To calculate the power of elements in an array we use the numpy.power() method of NumPy library.

It raises the values of the first array to the powers in the second array.

Example:

Python3

import numpy as np
# creating the array
sample_array1 = np.arange(5)
sample_array2 = np.arange(0, 10, 2)
print("Original array ")
print("array1 ", sample_array1)
print("array2 ", sample_array2)
# calculating element-wise power
power_array = np.power(sample_array1, sample_array2)
print("power to the array1 and array 2 : ", power_array)

Output:

Original array 
array1  [0 1 2 3 4]
array2  [0 2 4 6 8]
power to the array1 and array 2 :  [    1     1    16   729 65536]

Syntax

Syntax: numpy.power(arr1, arr2, out = None, where = True, casting = ‘same_kind’, order = ‘K’, dtype = None)

Parameters:

• arr1: Input array or object which works as base. 
• arr2: Input array or object which works as exponent. 
• out: Output array with same dimensions as Input array, placed with the result. 
• 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.

More Examples

Let’s look at more Python programs that shows how to find the Power of elements in the array using the power() function of the NumPy library.

Example 1: Computing the same power for every element in the array.

Python3

# import required module
import numpy as np


# creating the array
array = np.arange(8)
print("Original array")
print(array)

# computing the power of array
print("power of 3 for every element-wise:")
print(np.power(array, 3))

Output:

Original array
[0 1 2 3 4 5 6 7]
power of 3 for every element-wise:
[  0   1   8  27  64 125 216 343]

Example 2: Computing the power of decimal value.

Python3

# import required modules
import numpy as np


# creating the array
sample_array1 = np.arange(5)

# initialization the decimal number
sample_array2 = [1.0, 2.0, 3.0, 3.0, 2.0]

print("Original array ")
print("array1 ", sample_array1)
print("array2 ", sample_array2)

# calculating element-wise power
power_array = np.power(sample_array1, sample_array2)

print("power to the array1 and array 2 : ", power_array)

Output:

Original array 
array1  [0 1 2 3 4]
array2  [1.0, 2.0, 3.0, 3.0, 2.0]
power to the array1 and array 2 :  [ 0.  1.  8. 27. 16.]

Note: you can not compute negative power

Example 3: Computing negative power

Python3

# importing module
import numpy as np


# creating the array
array = np.arange(8)
print("Original array")
print(array)
print("power of 3 for every element-wise:")

# computing the negative power element
print(np.power(array, -3))

Output: