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
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Appendix C: The Complete UniPoly Class
Appendix D: The Complete Guitar Class Hierarchy
Appendix F: Production Notes

7.11 Class variables

An instance variable is unique to each object created by a class. A class variable is shared, accessible, and changeable by all objects of a class. There are similarities with the global variables we saw in section 6.9.2. Coders frequently use class variables instead of top level global variables. Restricting their use within a class is more acceptable, especially if their names start with “__”.

As we have seen, if obj is the name of an instance, you reference an instance variable with a name prefixed by “obj.”. obj is often self.

You define a class variable at the top level of a class, along with the instance methods.

class Guitar:
    number_of_guitars = 0

    def __init__(self, brand):
        Guitar.number_of_guitars += 1
        plural = "s" if Guitar.number_of_guitars != 1 else ""
        print(f"We have {Guitar.number_of_guitars...