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The range() Function in Python

Python supports object-oriented programming and has a concise, readable, and easy-to-learn syntax. It is no wonder that it is one of the most popular programming languages. An integral part of Python are its built-in functions. 

We've written a series of articles to help you learn and brush up on the most useful Python functions. In this article, we’ll learn about Python's range() function and how to use it. 

If you are preparing for a tech interview, check out our technical interview checklist, interview questions page, and salary negotiation e-book to get interview-ready! Also, read Python String join() Method, Python Exit commands, and Type and Isinstance In Python for more content on Python coding interview preparation.

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In this article, we’ll cover:

  • What Is the range() Function in Python and What Does It Do?
  • The range() Function in Python: Syntax
  • The range() Function in Python: Example
  • FAQs on the range() Function in Python

What Is the range() Function in Python and What Does It Do?

Python range() function is a built-in function we can use to generate a sequence of numbers within a given range. Through the number of arguments passed to the function, we can control where that sequence of numbers will begin and end, along with the difference between two successive numbers in the series. 

Python range() function is often used to iterate through a sequence using a for or while loop.

The range() Function in Python: Syntax


range(stopNumber)
range(startNumber, stopNumber)
range(startNumber, stopNumber, stepValue)

Parameters:

Python’s range() function takes three arguments:

  • startNumber (optional): The sequence of integers returned starts from this integer. If the starting integer is not provided, range() starts the sequence with zero (its default start value).
  • stopNumber: The sequence of integers that range() returns ends before this integer. The integer range ends at stopNumber – 1.
  • stepValue (optional): An integer value indicating the difference between each integer in the sequence. If we don’t pass the step value, then range() works with the default step value, one. The step value can be any integer other than zero. Passing zero as the step value will give an error.

Please note that:

  • When we call range() with one argument, we can choose where the sequence of numbers stops, starting at 0, with step 1 as default.
  • When we call range() with two arguments, we can choose where the sequence of numbers stops and starts. So our sequence doesn’t have to always start at zero. 
  • When we call range() with three arguments, we can decide where the sequence of numbers will start and stop as well as what the difference between two successive numbers in the sequence will be. The step value is a positive number for increments and a negative number for decrements.

Return Value:

Returns a sequence of integers with start, stop, and step values as decided by the parameters passed and defaults (for the parameters not provided).

The range() Function in Python: Example

Here, we take a look at how to use the range() function in Python next time you need it:

Code


# Using the range() function in Python

# With only stop parameter
print("Integers from 1 to 10-1 are: ")
for number in range(10):
    print(number, end=" ")
print()

# Iterating through a sequence using a for loop and len() as the stop parameter in range()
example = [1, 3, 5, 7]
print("All the numbers in the sequence example are: ")
for number in range(len(example)):
    print(example[number], end=" ")
print()

# With start and stop parameter
print("Integers from 5 to 10-1 are: ")
for number in range(5, 10):
    print(number, end=" ")
print()

# Calculating factorial
factorial = 1
for i in range(1, 6):
    factorial = factorial * i
print("The factorial of 5 is:", factorial)

# With start, stop, and step parameter
print("Integers from 1 to 10-1, with a step value of 2 are: ")
for number in range(1, 10, 2):
    print(number, end=" ")
print()

# Printing numbers divisible by 5
print("Integers divisible by 5 in the range [0, 50): ")
for number in range(0, 50, 5):
    print(number, end=" ")
print()

# Using a negative step value
print("Integers from 50 to 0+1, with a step value of -5 are: ")
for number in range(50, 0, -5):
    print(number, end=" ")
print()

# Accessing the proper list returned by range using an index

listReturned= range(50, 0, -5)
print("The number on index 3 in the above example is: ")
print(listReturned[3])

Output


Integers from 1 to 10-1 are: 
0 1 2 3 4 5 6 7 8 9 
All the numbers in the sequence example are: 
1 3 5 7 
Integers from 5 to 10-1 are: 
5 6 7 8 9 
The factorial of 5 is: 120
Integers from 1 to 10-1, with a step value of 2 are: 
1 3 5 7 9 
Integers divisible by 5 in the range [0, 50): 
0 5 10 15 20 25 30 35 40 45 
Integers from 50 to 0+1, with a step value of -5 are: 
50 45 40 35 30 25 20 15 10 5 
The number on index 3 in the above example is: 
35

Found this article helpful? You can learn about more Python functions on the learn page. 

FAQs on the range() Function in Python

Q1. What does the range() function in Python generate?

The Python range() function returns a series of integers with the start, stop, and step values as decided by the parameters passed and defaults (for the parameters not provided). The default start value is zero, and the default step value is one. 

Q2. What is the default start value in the range() function in Python?

The default value of the start parameter is zero in the range() function in Python.

Q3. What is the default step value in the range() function in Python?

The default value of the step parameter is one in the range() function in Python. 

Q4. How do you use the range() function in Python?

The syntax for range() is range(startNumber, stopNumber, stepValue), with startNumber and stepValue being optional parameters.

Q5. Does the end value parameter include itself in the range() function?

No. The range ends at endValue-1 and does not include the endValue itself in the Python range() function.

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Attend our Free Webinar on How to Nail Your Next Technical Interview

WEBINAR +LIVE Q&A

How To Nail Your Next Tech Interview

Hosted By
Ryan Valles
Founder, Interview Kickstart
Our tried & tested strategy for cracking interviews
How FAANG hiring process works
The 4 areas you must prepare for
How you can accelerate your learnings

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