sequence

In Python, a sequence is a collection of ordered objects where each object has an associated integer index that defines its position in the sequence. Sequences allow you to store multiple values in a single container object. You can access each value by its position (index) within the sequence.

Lists, tuples, and strings are common examples of sequences in Python. Each of these data types supports indexing, slicing, and iteration, making them versatile and powerful tools for managing data collections.

Sequences are fundamental in Python programming because they provide a way to handle collections of data efficiently. With sequences, you can perform operations like concatenation, repetition, and membership testing. You can also use built-in functions like len(), min(), and max() to perform common tasks.

Examples

Here’s a quick example of using a list, which is a sequence data type in Python:

Python 
>>> # Creating a list
>>> fruits = ["apple", "banana", "cherry", "grape"]

>>> # Accessing items by index
>>> fruits[0]
'apple'

>>> # Updating an existing item
>>> fruits[3] = "red grape"

>>> # Getting a slice for the list
>>> fruits[1:3]
['banana', 'cherry']

>>> # Adding an item to the list
>>> fruits.append("mango")

>>> # Iterate over the list
>>> for fruit in fruits:
...     print(fruit)
...
apple
banana
cherry
red grape
mango

In this example, you perform common sequence operations, such as creating a new list, accessing its items by index, assigning new values to a given item, retrieving a portion of the list, adding items to the list, and iterating over its items.

Note that you can only update values and add new values to mutable sequences like lists. Tuples and strings are immutable and don’t support in-place changes.

Here are some additional examples of using a string, another Python sequence:

Python 
>>> # Creating a string
>>> text = "apple"

>>> # Accessing characters by index
>>> text[0]
'a'

>>> # Getting a slice of the string
>>> text[1:4]
'ppl'

>>> # Iterating over the string
>>> for char in text:
...     print(char)
...
a
p
p
l
e

>>> # Trying to update a character
>>> text[0] = "A"
Traceback (most recent call last):
    ...
TypeError: 'str' object does not support item assignment

Strings are immutable. They support indexing, slicing, iteration as well as other common sequence operations. However, the don’t support item assignment as lists do.

Python Sequences: A Comprehensive Guide

Tutorial

Python Sequences: A Comprehensive Guide

This tutorial dives into Python sequences, which is one of the main categories of data types. You'll learn about the properties that make an object a sequence and how to create user-defined sequences.

intermediate python

For additional information on related topics, take a look at the following resources:

By Leodanis Pozo Ramos • Updated April 25, 2025
Python Glossary Share Feedback