Python Program to Find Absolute Value

Use the built-in function abs() in Python to find the absolute value of a number, for example, abs(-5) returns 5.

Examples

Input-10

Output10

Input0

Output0

Input7

Output7

How to Think About It

To find the absolute value, think about removing any negative sign from the number. If the number is negative, make it positive; if it is already positive or zero, keep it as is. This gives the distance of the number from zero on the number line.

Algorithm

1

Get the input number.

2

Check if the number is less than zero.

3

If yes, multiply the number by -1 to make it positive.

4

If no, keep the number as it is.

5

Return the resulting positive number.

Code

python

number = float(input('Enter a number: '))
absolute_value = abs(number)
print('Absolute value:', absolute_value)

Output

Enter a number: -8
Absolute value: 8.0

Dry Run

Let's trace the input -8 through the code

1

Input number

User enters -8, so number = -8.0

2

Calculate absolute value

abs(-8.0) returns 8.0

3

Print result

Prints 'Absolute value: 8.0'

Step	Variable	Value
1	number	-8.0
2	absolute_value	8.0

Why This Works

Step 1: Input number

The program reads the number entered by the user as a floating-point value.

Step 2: Use abs() function

The built-in abs() function returns the absolute value by removing any negative sign.

Step 3: Output result

The program prints the absolute value, showing the positive distance from zero.

Alternative Approaches

Using conditional statement

python

number = float(input('Enter a number: '))
if number < 0:
    absolute_value = -number
else:
    absolute_value = number
print('Absolute value:', absolute_value)

This method manually checks the sign and converts negative numbers to positive, useful if you want to avoid built-in functions.

Using math module

python

import math
number = float(input('Enter a number: '))
absolute_value = math.fabs(number)
print('Absolute value:', absolute_value)

The <code>math.fabs()</code> function returns the absolute value as a float, similar to <code>abs()</code> but always returns float.

Complexity: O(1) time, O(1) space

Time Complexity

Finding the absolute value is a single operation with no loops, so it runs in constant time O(1).

Space Complexity

The program uses a fixed amount of memory for variables, so space complexity is O(1).

Which Approach is Fastest?

Using the built-in abs() is fastest and most readable; manual condition checks add unnecessary code.

Approach	Time	Space	Best For
Built-in abs()	O(1)	O(1)	Simplicity and speed
Conditional check	O(1)	O(1)	Understanding logic without built-ins
math.fabs()	O(1)	O(1)	When working with math module functions