Book Image

Python Data Structures and Algorithms

By : Benjamin Baka
Book Image

Python Data Structures and Algorithms

By: Benjamin Baka

Overview of this book

Data structures allow you to organize data in a particular way efficiently. They are critical to any problem, provide a complete solution, and act like reusable code. In this book, you will learn the essential Python data structures and the most common algorithms. With this easy-to-read book, you will be able to understand the power of linked lists, double linked lists, and circular linked lists. You will be able to create complex data structures such as graphs, stacks and queues. We will explore the application of binary searches and binary search trees. You will learn the common techniques and structures used in tasks such as preprocessing, modeling, and transforming data. We will also discuss how to organize your code in a manageable, consistent, and extendable way. The book will explore in detail sorting algorithms such as bubble sort, selection sort, insertion sort, and merge sort. By the end of the book, you will learn how to build components that are easy to understand, debug, and use in different applications.
Table of Contents (20 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
5
Stacks and Queues
7
Hashing and Symbol Tables

Singly linked lists


A singly linked list is a list with only one pointer between two successive nodes. It can only be traversed in a single direction, that is, you can go from the first node in the list to the last node, but you cannot move from the last node to the first node.

We can actually use the node class that we created earlier to implement a very simple singly linked list:

>>> n1 = Node('eggs')
    >>> n2 = Node('ham')
    >>> n3 = Node('spam')

Next we link the nodes together so that they form a chain:

>>> n1.next = n2
    >>> n2.next = n3

To traverse the list, you could do something like the following. We start by setting the variable current to the first item in the list:

    current = n1
    while current:
        print(current.data)
        current = current.next 

In the loop we print out the current element after which we set current to point to the next element in the list. We keep doing this until we have reached the end of the list.

There...