#### Overview of this book

Choosing the right data structure is pivotal to optimizing the performance and scalability of applications. This new edition of Hands-On Data Structures and Algorithms with Python will expand your understanding of key structures, including stacks, queues, and lists, and also show you how to apply priority queues and heaps in applications. You’ll learn how to analyze and compare Python algorithms, and understand which algorithms should be used for a problem based on running time and computational complexity. You will also become confident organizing your code in a manageable, consistent, and scalable way, which will boost your productivity as a Python developer. By the end of this Python book, you’ll be able to manipulate the most important data structures and algorithms to more efficiently store, organize, and access data in your applications.
Preface
Free Chapter
Python Data Types and Structures
Introduction to Algorithm Design
Algorithm Design Techniques and Strategies
Stacks and Queues
Trees
Heaps and Priority Queues
Hash Tables
Graphs and Algorithms
Searching
Sorting
Selection Algorithms
String Matching Algorithms
Other Books You May Enjoy
Index

# String notations and concepts

Strings are sequences of characters. Python provides a rich set of operations and functions that can be applied to the string data type. Strings are textual data and are handled very efficiently in Python. The following is an example of a string `(s)``"packt publishing"`.

A substring is a sequence of characters that’s part of the given string, i.e., specified indices in the string in a continuous order. For example, “`packt`" is a substring of the string “`packt publishing`". On the other hand, a subsequence is also a sequence of characters that can be obtained from the given string by removing some of the characters from the string by keeping the order of occurrence of the characters. For example, “`pct pblishing`" is a valid subsequence for the string “`packt publishing`" that is obtained by removing the characters `a`, `k`, and `u`. However, this is not a substring since “`pct pblishing...`