# Introduction to Python Range Function

The range function in Python returns a sequence of numbers starting from the given input value (by default: 0), increments the number at the defined step size (by default: 1), and stops before the specified value. In this article, we will discuss python range function, and how to use them.

Python offers a number of built-in functions and types that are always available to use. In this article, we will discuss one such built-in function that represents an immutable sequence of numbers and is commonly used for looping a specific number of times in the for loops.

**Must Read:** For Loop in Python (Practice Examples)

**Must Check:** Python Online Course and Certification

**Table of Content**

**What is Python Range Function?**

**Definition**

The range function in Python returns a sequence of numbers starting from the given input value (by default: 0), increments the number at the defined step size (by default: 1), and stops before the specified value.

- range () functions are most commonly used for loops to iterate sequences on a sequence of numbers.
- range () function only takes integer values.

**Syntax**

range (start, stop, step_size)

**Parameter**

**start**: the value from where the sequence will start.- It is optional.
- If not defined, the value starts from 0.

**stop**: the next value after the sequence will stop.- Not optional.

**step_size**: denotes the difference between two values, i.e., how much we have to add to get the next value.- It is optional.
- If not defined, the step_size will be 1.
- The value should be an integer value (whole number)
- if step_size = 0, it will throw an error.

**How to use the Python Range function?**

Python range() functions are used in three different formats, depending on the number of parameters used at a time.

**range (stop)**

range (stop) function will return the list of values from 0 to stop โ 1. It will take only positive values.

- range(stop) function considers only positive integers
- If you input a floating value (or any other data type in Python), it will return a TypError.
- If we input a negative value, it will show nothing.

Letโs take some examples:

**Example 1:**

#print the first 10 whole numbernumber = range(10)print(list(number))

**Output**

**Example 2:**

#print the first 10 integers using for loop
for i in range(10): print(i, end =" ")print()

**Output**

**Example 3**

#using a negative value for the stop
for i in range(-10): print(i, end =" ")print()

**Output**

nothing

**Example 4**

#using a floating value for the stopfor i in range(10.5): print(i, end =" ")print()

**Output**

**range (start, stop)**

Here, we will use two parameters (or arguments) with the range() function, i.e., start and stop. As a result, we will get the sequence of integers as a** start, start + 1, start + 2, start + 3, โฆโฆ., stop -1**.

**Note: **Here, the start and stop values can be either positive or negative.

Letโs move to examples:

**Example โ 1:**

# start and stop both are positive#list the number of integers between 5 to 10.for i in range(5, 10): print(i, end =" ")print()

**Output**

**Example โ 2**

# start = -ve & stop = +ve#list the number of integers between -5 to 10.for i in range(-5, 10): print(i, end =" ")print()

**Output**

**Example -3**

#start and stop both are negative#list the number of integers between -10 to -5.for i in range(-10, -5): print(i, end =" ")print()

**Output**

**range (start, stop, step_size)**

Here, we will use all three parameters with the range function, i.e., start, stop, and step size.

- It is used when we donโt want to traverse an iterable sequentially but want to access every n-th value of the sequence.
- range(start, stop, step_size) will produce a sequence such as:

**start, start + step, start + 2*step, start + 3*step, โฆโฆ., start + n *step**,

where,

**start + n*step < stop < start + (n+1) step**.

- Here, the value of step size can be negative.
- In this case,
**start > stop**.

- In this case,

Letโs take some examples:

**Example-1:**

#list the number of integers between 0 to 20 at the step size of 2for i in range (0, 20, 2): print(i, end =" ")print()

**Output**

**Example -2**

#negative step-size#lsit the number of integers between 0 to 20 at the step size of -2for i in range (20, 0, -2): print(i, end =" ")print()

**Output**

**Reversed Range**

How will you reverse the output produced by the range() function?

In Python, we can do it in two ways:

- By negative step size (step size = -1)
- By reverse function
- reversed (range()) function displays the sequence of numbers produced by the range() function in descending or reversed order.

Letโs take an example to know how it works:

#using reversed function#lsit the number of integers (in decreasing order) between 0 to 20 at the step size of 2for i in reversed(range (0, 20, 2)): print(i, end =" ")print()

**Output**

**Conclusion**

In this article, we have briefly discussed the range () function in Python, with examples of how it works in different conditions.

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**About the Author**

Vikram has a Postgraduate degree in Applied Mathematics, with a keen interest in Data Science and Machine Learning. He has experience of 2+ years in content creation in Mathematics, Statistics, Data Science, and Mac... Read Full Bio