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:
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