Python range() function

The range() function in Python is used to generate a sequence of integers within a specified range. It is most commonly used in loops to control how many times a block of code runs.

Note: range() returns a lazy iterable, not a full list. It generates numbers dynamically instead of storing them all in memory.. To access elements like a list, convert it using list(range(...)).

Example: This example shows the use of range() to generate numbers starting from 0 up to (but not including) a given value.

0 1 2 3 4 

Explanation:

• range(5) generates numbers from 0 to 4
• i takes one value at a time from the generated sequence

Syntax

range(start, stop, step)

Parameters:

• start (optional): Starting number of the sequence (default is 0)
• stop: Number at which the sequence stops (not included)
• step (optional): Difference between consecutive numbers (default is 1)

Return: A range object representing the sequence

Examples

Example 1: This example generates numbers starting from a custom value and ending before another value.

5 6 7 8 9 

Explanation:

• range(5, 10) starts at 5 and stops before 10
• Numbers increase by the default step of 1

Example 2: This example generates even numbers by skipping values using a custom step size.

0 2 4 6 8 

Explanation:

• range(0, 10, 2) increases the value by 2 each time
• The step controls how much the number changes per iteration

Example 3: This example demonstrates how range() can be used to generate numbers in reverse order by providing a negative step value.

10 8 6 4 2 

Explanation:

• range(10, 0, -2) starts from 10 and decreases by 2 each time
• A negative step allows backward iteration through numbers