Book Image

Learning Python

By : Fabrizio Romano
Book Image

Learning Python

By: Fabrizio Romano

Overview of this book

Learning Python has a dynamic and varied nature. It reads easily and lays a good foundation for those who are interested in digging deeper. It has a practical and example-oriented approach through which both the introductory and the advanced topics are explained. Starting with the fundamentals of programming and Python, it ends by exploring very different topics, like GUIs, web apps and data science. The book takes you all the way to creating a fully fledged application. The book begins by exploring the essentials of programming, data structures and teaches you how to manipulate them. It then moves on to controlling the flow of a program and writing reusable and error proof code. You will then explore different programming paradigms that will allow you to find the best approach to any situation, and also learn how to perform performance optimization as well as effective debugging. Throughout, the book steers you through the various types of applications, and it concludes with a complete mini website built upon all the concepts that you learned.
Table of Contents (20 chapters)
Learning Python
Credits
About the Author
Acknowledgements
About the Reviewers
www.PacktPub.com
Preface
Index

Generation behavior in built-ins


Amongst the built-in types, the generation behavior is now quite common. This is a major difference between Python 2 and Python 3. A lot of functions such as map, zip, and filter have been transformed so that they return objects that behave like iterables. The idea behind this change is that if you need to make a list of those results you can always wrap the call in a list() class, and you're done. On the other hand, if you just need to iterate and want to keep the impact on memory as light as possible, you can use those functions safely.

Another notable example is the range function. In Python 2 it returns a list, and there is another function called xrange that returns an object that you can iterate on, which generates the numbers on the fly. In Python 3 this function has gone, and range now behaves like it.

But this concept in general is now quite widespread. You can find it in the open() function, which is used to operate on file objects (we'll see it in...