> For the complete documentation index, see [llms.txt](https://kallyasmedia.gitbook.io/cit-python-cohort-three/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://kallyasmedia.gitbook.io/cit-python-cohort-three/week6/data_structures_and_algorithms/linked_list.md).

# Linked List

A linked list is a linear data structure that includes a series of connected nodes. Here, each node stores the data and the address of the next node. For example,

![Linked list data structure](https://cdn.programiz.com/sites/tutorial2program/files/linked-list-concept.png)

You have to start somewhere, so we give the address of the first node a special name called `HEAD`. Also, the last node in the linked list can be identified because its next portion points to NULL.

Linked lists can be of multiple types: singly, doubly, and circular linked list. In this article, we will focus on the singly linked list.

> **NOTE**: You might have played the game Treasure Hunt, where each clue includes the information about the next clue. That is how the linked list operates.

### Representation of Linked List

Let's see how each node of the linked list is represented. Each node consists:

* A data item
* An address of another node

```python
class Node:
    def __init__(self, data):
        self.data = data
        self.next = None

class LinkedList:
    def __init__(self):
        self.head = None

    def print_list(self):
        temp = self.head
        while temp:
            print(temp.data)
            temp = temp.next

if __name__ == '__main__':
    llist = LinkedList()
    llist.head = Node(1)
    second = Node(2)
    third = Node(3)

    llist.head.next = second
    second.next = third

    llist.print_list()
```

### Linked List Applications

Linked lists are used in many applications. Some of them are:

* Dynamic memory allocation
* Implemented in stack and queue
* In undo functionality of softwares
* Hash tables, Graphs


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://kallyasmedia.gitbook.io/cit-python-cohort-three/week6/data_structures_and_algorithms/linked_list.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.