Using the range() Function in Python

The range() function is a built-in function in Python that generates a sequence of numbers. The sequence generated by range() is an immutable sequence, which means that it cannot be modified once it is created. The range() function takes three arguments: start, stop, and step.

• start: The starting number of the sequence. If this argument is not provided, it defaults to 0.
• stop: The ending number of the sequence. This argument is required and cannot be omitted. Note that the ending number is exclusive, i.e., the sequence will not include this number.
• step: The difference between each number in the sequence. If this argument is not provided, it defaults to 1.

How to Use the Range Function in Python

Example 1: Generating a Sequence of Numbers

To generate a sequence of numbers using the range() function, simply pass the start and stop arguments to the function. The following code generates a sequence of numbers from 0 to 4:

for i in range(5):
    print(i)

Output:

0
1
2
3
4

Example 2: Generating a Sequence of Numbers with a Start Value

To generate a sequence of numbers with a start value other than 0, pass the start argument to the range() function. The following code generates a sequence of numbers from 2 to 6:

for i in range(2, 7):
    print(i)

Output:

2
3
4
5
6

Example 3: Generating a Sequence of Numbers with a Step Value

To generate a sequence of numbers with a step value other than 1, pass the step argument to the range() function. The following code generates a sequence of numbers from 0 to 10 with a step value of 2:

for i in range(0, 11, 2):
    print(i)

Output:

0
2
4
6
8
10

Example 4: Generating a Sequence of Numbers in Reverse Order

To generate a sequence of numbers in reverse order, pass a negative step argument to the range() function. The following code generates a sequence of numbers from 10 to 0:

for i in range(10, -1, -1):
    print(i)

Output:

10
9
8
7
6
5
4
3
2
1
0

Example 5: Creating a List of Numbers

The range() function can also be used to create a list of numbers. To do this, simply pass the start, stop, and step arguments to the range() function and convert the result to a list using the list() function. The following code creates a list of even numbers from 0 to 10:

even_numbers = list(range(0, 11, 2))
print(even_numbers)

Output:

[0, 2, 4, 6, 8, 10]

Conclusion

The range() function is a useful tool for generating a sequence of numbers in Python. By providing the start, stop, and step arguments to the range() function, you can create a sequence of numbers with custom starting values, step values, and even in reverse order. Additionally, the range() function can be used to create a list of numbers by converting the result to a list using the list() function.

It’s important to note that the range() function in Python 3.x returns a range object, which is a memory-efficient representation of the sequence of numbers. The range object behaves like a list in many ways, but it is not actually a list. If you need a real list, you can use the list() function to convert the range object to a list.

Overall, understanding how to use the range() function is an important skill for any Python programmer, as it can help you generate sequences of numbers quickly and efficiently in your code.