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

Selection by sorting


Items in a list may undergo statistical enquiries such as finding the mean, median, and mode values. Finding the mean and mode values do not require the list to be ordered. However, to find the median in a list of numbers, the list must first be ordered. Finding the median requires one to find the element in the middle position of the ordered list. But what if we want to find the last-smallest item in the list or the first-smallest item in the list?

To find the ith-smallest number in an unordered list of items, the index of where that item occurs is important to obtain. But because the elements have not been sorted, it is difficult to know whether the element at index 0 in a list is really the first-smallest number.

A pragmatic and obvious thing to do when dealing with unordered lists is to first sort the list. Once the list is sorted, one is assured that the zeroth element in the list will house the first-smallest element in the list. Likewise, the last element in the...