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)
2
Part I: Getting to Know Python
10
PART II: Algorithms and Circuits
14
PART III: Advanced Features and Libraries
19
References
20
Other Books You May Enjoy
Appendices
Appendix C: The Complete UniPoly Class
Appendix D: The Complete Guitar Class Hierarchy
Appendix F: Production Notes

4.3 Accessing characters

Valid indices for strings range from the negative string length to one less than the string length.

guitars = "Fender Gibson Taylor"
guitars[0]
'F'
guitars[-1]
'r'
guitars[-5]
'a'

Use find to locate a substring within an index range in a string. If my_string is a string, then find can have from one to three arguments.

my_string.find(substring, start_index=0, end_index=len(my_string))

This notation means that one argument is required, which is the substring for which you are looking. If you give no other arguments, find starts looking at index 0. If you do not give the third argument, it defaults to the length of the string.

guitars.find("o")
11
guitars.find("o", 12)
18
guitars.find("o", 2, 9)
-1

If Python cannot locate the substring, find returns...