Book Image

Secret Recipes of the Python Ninja

Book Image

Secret Recipes of the Python Ninja

Overview of this book

This book covers the unexplored secrets of Python, delve into its depths, and uncover its mysteries. You’ll unearth secrets related to the implementation of the standard library, by looking at how modules actually work. You’ll understand the implementation of collections, decimals, and fraction modules. If you haven’t used decorators, coroutines, and generator functions much before, as you make your way through the recipes, you’ll learn what you’ve been missing out on. We’ll cover internal special methods in detail, so you understand what they are and how they can be used to improve the engineering decisions you make. Next, you’ll explore the CPython interpreter, which is a treasure trove of secret hacks that not many programmers are aware of. We’ll take you through the depths of the PyPy project, where you’ll come across several exciting ways that you can improve speed and concurrency. Finally, we’ll take time to explore the PEPs of the latest versions to discover some interesting hacks.
Table of Contents (17 chapters)
Title Page
Copyright and Credits
Packt Upsell
Foreword
Contributors
Preface
Index

Making scripts executable


Normally, executing a Python program requires typing python <program>.py. However, it is possible to make Python programs self-executing so they don't require typing python as the calling command.

How to do it...

  1. On *NIX systems, putting #!/usr/bin/env python as the first line of a program allows the program to be executable by referencing the location of Python on the user's PATH. Of course, this assumes Python is on the PATH; if not, then the program will have to be invoked like normal.
  2. After this has been added to the program, the file itself needs to be modified to make it executable, that is, $ chmod +x <program>.py.
  3. If you are using a terminal program that displays files and directories in different colors depending on their modes, running the command ls on the directory where the file is located should show it with a different color than non-executable files.
  4. To execute the program, simply type ./<program>.py and the program will execute without...