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Learn Python Programming

You're reading from   Learn Python Programming The no-nonsense, beginner's guide to programming, data science, and web development with Python 3.7

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Product type Paperback
Published in Jun 2018
Publisher Packt
ISBN-13 9781788996662
Length 508 pages
Edition 2nd Edition
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Author (1):
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Fabrizio Romano Fabrizio Romano
Author Profile Icon Fabrizio Romano
Fabrizio Romano
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Table of Contents (16) Chapters Close

Preface 1. A Gentle Introduction to Python FREE CHAPTER 2. Built-in Data Types 3. Iterating and Making Decisions 4. Functions, the Building Blocks of Code 5. Saving Time and Memory 6. OOP, Decorators, and Iterators 7. Files and Data Persistence 8. Testing, Profiling, and Dealing with Exceptions 9. Cryptography and Tokens 10. Concurrent Execution 11. Debugging and Troubleshooting 12. GUIs and Scripts 13. Data Science 14. Web Development 15. Other Books You May Enjoy

Anonymous functions

One last type of functions that I want to talk about are anonymous functions. These functions, which are called lambdas in Python, are usually used when a fully-fledged function with its own name would be overkill, and all we want is a quick, simple one-liner that does the job.

Imagine that you want a list of all the numbers up to N that are multiples of five. Imagine that you want to filter those out using the filter function, which takes a function and an iterable and constructs a filter object that you can iterate on, from those elements of iterables for which the function returns True. Without using an anonymous function, you would do something like this:

# filter.regular.py
def is_multiple_of_five(n):
return not n % 5

def get_multiples_of_five(n):
return list(filter(is_multiple_of_five, range(n)))

Note how we use is_multiple_of_five to filter the first...

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