How to Calculate Absolute Value in Python

In this article, we’ll show you how to calculate absolute value in Python. Here’s how to accomplish this task.

• Using a User-Defined Function (Brute Force Method)

• Using the abs() Function

• Using the math.fabs() Function

The magnitude of a number, whether positive or negative, is called its absolute value. For example, the absolute value of -2 is 2, while 2 is just 2.

Important Note

• The absolute value is returned by the built-in abs() function.

• math.fabs() also returns an absolute value, but it is a floating-point value.

• When we pass an integer or floating-point number to abs(), we get the absolute integer or floating-point value back.

• However, if we pass a complex number to abs(), the function returns the magnitude of that number.

Using User-Defined Functions (Brute Force Method)

Algorithm (Steps)

Below are the algorithm/steps you need to follow to perform the desired task.

• Create a function that returns the absolute value of the number passed to it as an argument.

• Use an if condition statement to check if the number is less than 0.

• If the condition is true, the negative of the value is returned. That is, the – value becomes the plus (+), which is the absolute value.

• If the number is positive, the passed number is returned directly.

The following program returns the absolute value of a number –

# creating a function that returns the absolute value
def getAbsoluteValue(value):
# checking whether the number is less than 0
if(value<0):
# returning the negative of the value if the condition is true
# i.e. -(-) value becomes plus(+)
return -value
# returning the number passed
return value
# calling the getAbsoluteValue() function by passing some random positive number
print("Absolute value of 5 = ", getAbsoluteValue(5))
# calling the getAbsoluteValue() function by passing some random negative number
print("Absolute value of -5 = ", getAbsoluteValue(-5))

Output

Upon execution, the above program will produce the following output

Absolute value of 5 = 5
Absolute value of -5 = 5

Using the abs() Function

abs() is used to find the absolute value of a number. It can be applied to both real and complex numbers.

Syntax

abs(number)

When applied to a real number, the abs() function returns the magnitude of that number. A real number is defined as lying on the number line, as shown in the figure below. The magnitude of a real number is its distance along the line from the origin.

The sign of a number indicates the direction of the number along the line; positive values lie along the positive axis, and negative values lie along the negative axis. In the quick introduction example, -5 is a real number.

Using abs() to calculate the absolute value of an integer

The following program uses the abs() function to return the absolute value of an integer –

# input numbers(integers)
num_1 = 4
num_2 = -6
num_3 = 0
num_4 = -875
# calculating absolute values of input integers
print("absolute value of 4 = ", abs(num_1))
print("absolute value of -6 = ", abs(num_2))
print("absolute value of 0 = ", abs(num_3))
print("absolute value of -875 = ", abs(num_4))

Output

When executed, the above program will produce the following output

absolute value of -4.5 = 4.5
absolute value of 6.789 = 6.789
absolute value of -10.56 = 10.56
absolute value of 8.23 = 8.23

Using abs() to Calculate the Absolute Value of a Complex Number

abs() can also be used on complex numbers.

A complex number consists of a real number and an imaginary number. Imaginary numbers are represented by the square root of a negative number. They are usually represented by their value, i.e., the square root of -1.

Imaginary numbers fill many mathematical gaps. Therefore, they are widely used in math-intensive fields, especially in electrical engineering. An example of a complex number is shown in the figure below.

• If we pass a complex number to abs() , the function returns the magnitude of the number.

For example

The following program uses the abs() function to return the absolute value of a complex number.

# Input complex numbers
num_1 = 4+5j
num_2 = 2-3j
num_3 = -3-4j
# Calculating absolute values of input complex numbers
print("absolute value of 4+5j = ", abs(num_1))
print("absolute value of 2-3j = ", abs(num_2))
print("absolute value of -3-4j = ", abs(num_3))

Output

When executed, the above program will produce the following output

absolute value of 4+5j = 6.4031242374328485
absolute value of 2-3j = 3.605551275463989
absolute value of -3-4j = 5.0

Using the math.fabs() Function to Calculate the Absolute Value of a Number

In addition to the standard abs() method, Python also has the math.fabs() function. This function also takes a single argument and returns the absolute value of that argument as a floating-point value.

The following program uses the abs() function to return the absolute value of a complex number.

# importing math module
import math
# input numbers
num_1 = 4
num_2 = -6.5
num_3 = -5
num_4 = -8
# calculating absolute values of input numbers as floating-point numbers
print("absolute value of 4 = ", math.fabs(num_1))
print("absolute value of -6.5 = ", math.fabs(num_2))
print("absolute value of -5 = ", math.fabs(num_3))
print("absolute value of -8.65 = ", math.fabs(num_4))

Output

When executed, the above program will produce the following output

absolute value of 4 = 4.0
absolute value of -6.5 = 6.5
absolute value of -5 = 5.0
absolute value of -8.65 = 8.0

Summary

In this tutorial, we introduced how to calculate absolute value in Python using three different methods. We also learned how to determine the absolute value of a complex number and a floating-point number through examples.