Book Image

Dancing with Python

By : Robert S. Sutor
Book Image

Dancing with Python

By: Robert S. Sutor

Overview of this book

Dancing with Python helps you learn Python and quantum computing in a practical way. It will help you explore how to work with numbers, strings, collections, iterators, and files. The book goes beyond functions and classes and teaches you to use Python and Qiskit to create gates and circuits for classical and quantum computing. Learn how quantum extends traditional techniques using the Grover Search Algorithm and the code that implements it. Dive into some advanced and widely used applications of Python and revisit strings with more sophisticated tools, such as regular expressions and basic natural language processing (NLP). The final chapters introduce you to data analysis, visualizations, and supervised and unsupervised machine learning. By the end of the book, you will be proficient in programming the latest and most powerful quantum computers, the Pythonic way.
Table of Contents (29 chapters)
Part I: Getting to Know Python
PART II: Algorithms and Circuits
PART III: Advanced Features and Libraries
Other Books You May Enjoy
Appendix C: The Complete UniPoly Class
Appendix D: The Complete Guitar Class Hierarchy
Appendix F: Production Notes

2.7 String operations

In this section, we work with this line fragment from Shakespeare’s Hamlet:

quote = "perchance to dream"
'perchance to dream'

Since we’ll need it several times, let’s save the number of characters in the str.

quote_length = len(quote)

2.7.1 Accessing characters

The first character is at index 0, and the last is at index quote_length - 1.

quote[quote_length - 1]

Python raises an error if you try to access a character beyond this final valid index.

IndexError: string index out of range

Exercise 2.10

What happens if you try to access a character at index 0 in an empty string?

Python does something interesting if you use a negative integer as an index.