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Learn Python Programming, 3rd edition

You're reading from   Learn Python Programming, 3rd edition An in-depth introduction to the fundamentals of Python

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Product type Paperback
Published in Oct 2021
Publisher Packt
ISBN-13 9781801815093
Length 554 pages
Edition 3rd Edition
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Authors (2):
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Heinrich Kruger Heinrich Kruger
Author Profile Icon Heinrich Kruger
Heinrich Kruger
Fabrizio Romano Fabrizio Romano
Author Profile Icon Fabrizio Romano
Fabrizio Romano
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Table of Contents (18) Chapters Close

Preface 1. A Gentle Introduction to Python 2. Built-In Data Types FREE CHAPTER 3. Conditionals and Iteration 4. Functions, the Building Blocks of Code 5. Comprehensions and Generators 6. OOP, Decorators, and Iterators 7. Exceptions and Context Managers 8. Files and Data Persistence 9. Cryptography and Tokens 10. Testing 11. Debugging and Profiling 12. GUIs and Scripting 13. Data Science in Brief 14. Introduction to API Development 15. Packaging Python Applications 16. Other Books You May Enjoy
17. Index

Recursive functions

When a function calls itself to produce a result, it is said to be recursive. Sometimes recursive functions are very useful, in that they make it easier to write code—some algorithms are very easy to write using the recursive paradigm, while others are not. There is no recursive function that cannot be rewritten in an iterative fashion, so it's usually up to the programmer to choose the best approach for the case at hand.

The body of a recursive function usually has two sections: one where the return value depends on a subsequent call to itself, and one where it doesn't (called the base case).

As an example, we can consider the (hopefully now familiar) factorial function, N!. The base case is when N is either 0 or 1—the function returns 1 with no need for further calculation. On the other hand, in the general case, N! returns the product:

1 * 2 * ... * (N-1) * N 

If you think about it, N! can be rewritten like this...

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