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Modern Python Cookbook

You're reading from   Modern Python Cookbook 133 recipes to develop flawless and expressive programs in Python 3.8

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Product type Paperback
Published in Jul 2020
Publisher Packt
ISBN-13 9781800207455
Length 822 pages
Edition 2nd Edition
Languages
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Author (1):
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Steven F. Lott Steven F. Lott
Author Profile Icon Steven F. Lott
Steven F. Lott
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Toc

Table of Contents (18) Chapters Close

Preface 1. Numbers, Strings, and Tuples 2. Statements and Syntax FREE CHAPTER 3. Function Definitions 4. Built-In Data Structures Part 1: Lists and Sets 5. Built-In Data Structures Part 2: Dictionaries 6. User Inputs and Outputs 7. Basics of Classes and Objects 8. More Advanced Class Design 9. Functional Programming Features 10. Input/Output, Physical Format, and Logical Layout 11. Testing 12. Web Services 13. Application Integration: Configuration 14. Application Integration: Combination 15. Statistical Programming and Linear Regression 16. Other Books You May Enjoy
17. Index

Using frozen dataclasses for immutable objects

In the Using typing.NamedTuple for immutable objects recipe, we saw how to define a class that has a fixed set of attributes. The attributes can be checked by the mypy program to ensure that they're being used properly. In some cases, we might want to make use of the slightly more flexible dataclass to create an immutable object.

One potential reason for using a dataclass is because it can have more complex field definitions than a NamedTuple subclass. Another potential reason is the ability to customize initialization and the hashing function that is created. Because a typing.NamedTuple is essentially a tuple, there's limited ability to fine-tune the behavior of the instances in this class.

Getting ready

We'll revisit the idea of defining simple playing cards with rank and suit. The rank can be modeled by an integer between 1 (ace) and 13 (king.) The suit can be modeled by a single Unicode character from...

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