.abs()

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Published Jun 16, 2024
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In NumPy, the .abs() function calculates the absolute value of a given number or each element in an array. The absolute value of a number is its non-negative value or the number’s distance from zero. This function can be applied to both real and complex numbers.

Note: numpy.abs() is identical to numpy.absolute(), and they can be used interchangeably.

Syntax

numpy.abs(input_value, out=None, where=True)

or alternatively,

numpy.absolute(input_value, out=None, where=True)
  • input_value: The input number or array for which the absolute value will be computed.
  • out (optional): A location where the result of the absolute value will be stored. If no value is provided, the default value of None is used and a new array is returned.
  • where (optional): A boolean array that determines which elements of the input array should have the absolute value function applied:
    • If the condition is True at a given position, the absolute value is computed for that element.
    • If the condition is False, the original value is retained.
    • If no value is provided, the absolute value is computed for every element.

Example 1

This example demonstrates using .abs() function to calculate the absolute value of an array:

# Importing the 'numpy' library as 'np'
import numpy as np
# Creating a numpy array
arr = np.array([1, -1.5, 0, -3])
# Computing the absolute value of the array
arr = np.abs(arr)
print(arr)

The above example code results in the following output:

[1. 1.5 0. 3.]

Example 2

This example shows how the where parameter of .abs() function is used to specify which elements of the array undergo the absolute value function:

# Importing the 'numpy' library as 'np'
import numpy as np
# Creating a numpy array
arr = np.array([-1, -2, -3, -4])
# Computing the absolute value of only the elements that are less than -2
np.abs(arr, out=arr, where=arr<-2)
print(arr)

The above example code results in the following output:

[-1 -2 3 4]

Note: The where array must be broadcastable to the shape of the input array. Additionally, when using the where parameter, it is recommended to use the out parameter to specify where the result should be stored, which helps avoid errors with uninitialized memory.

Codebyte Example

In this codebyte example, the .abs() method computes the absolute value of the elements in the array that are greater than -100:

Code
Output
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