22 Examples of Recursive Functions in Python
Mon 04 October 2021 Al Sweigart
Here are 22 actual, runnable Python code for several recursive functions, written in a style to be understandable by beginners and produce debuggable output.
What is a Python Generator? (Implementing Your Own range() Function)
Fri 24 September 2021 Al Sweigart
Generators in Python (also called generator functions) are used to create a series of values one at a time. Let's learn how they work by re-creating the built-in
range() function.
Recursion Is Not A Superpower: An Iterative Ackermann
Sun 05 September 2021 Al Sweigart
This post has the Python code for the infamously recursive Ackermann function, but without using recursion.
Algorithmic Art with the BitFieldDraw Module
Mon 02 August 2021 Al Sweigart
I created the bitfielddraw Python module so that you could turn math formulas into .png image files.
Combinations and Permutations in Python with itertools
Sat 03 July 2021 Al Sweigart
Explores the difference between combinations and permutations, and why you don't need to write your own Python code for them because the built-in
itertools module already exists. Includes working code examples.
Al Sweigart's PyTennessee 2020 Opening Keynote
Sun 07 March 2021 Al Sweigart
In March 2020, just before the lockdowns would begin, I gave the opening keynote at PyTennessee 2020. Unfortunately, it wasn't recorded. But I still have the script I used and so I re-recorded the talk. I've posted it to my YouTube channel.
Text Recognition in Python with pytesseract
Mon 11 January 2021 Al Sweigart
Extracting text as string values from images is called optical character recognition (OCR) or simply text recognition. This blog post tells you how to run the Tesseract OCR engine from Python. Includes working code examples.
A Quick Pip Guide: How to Install Python Modules
Mon 11 January 2021 Al Sweigart
This tutorial teaches you about Pip, a package manager that installs third-party packages for Python.
Type Hints for Busy Python Programmers
Sun 24 November 2019 Al Sweigart
A quick guide to using type hints in Python.
Python Error Messages: Gotta Catch Em All
Thu 15 August 2019 Al Sweigart
To make errors less intimidating, I've created a "Gotta Catch 'em All" worksheet that lists several common Python error messages. Instead of trying to avoid errors, beginners can try to hunt and collect them all.
Pythonic Ways to Use Dictionaries
Wed 05 June 2019 Al Sweigart
Python dictionaries are a useful part of the language. In addition to having the ability to store keys and values, you can also use dictionary methods to manipulate those values, and you can use dictionaries to write more concise code.
Hashable Objects Must Be Immutable
Fri 01 February 2019 Al Sweigart
A recent post to Reddit sparked some comments, so I wanted to clarify: In Python, hashable objects must be immutable and mutable objects cannot be hashable. (With one exception.)
A Curriculum for Python Packaging
Mon 22 October 2018 Al Sweigart
Python's packaging ecosystem contains multitudes. It can be intimidating for new Python developers to try to crack into, especially given the rapid evolution of Python packaging. Writing a *helloworld.py* file and running it on your computer is simple, but getting it to run on someone else's computer (and doing this the "right" way) involves a tangle of terms, tools, and techniques. What are wheel files? What is distutils? Do I use distutils or easy_install or pip?
To get to the bottom of this myself, I've compiled a curriculum of PyCon talks, online documentation, and my own personal notes to finally get a complete handle on Python packaging.
Writing Bots to Play Zombie Dice
Wed 17 October 2018 Al Sweigart
Programming games are a games genre where instead of playing the game directly, players write bot programs to play the game autonomously. I've created a Zombie Dice simulator, allowing programmers to practice their skills while having fun making game-playing AIs. Zombie Dice bots can be simple or incredibly complex, and are great for a class exercise or an individual programming challenge.
PyOhio 2018 Recursion Tutorial
Fri 24 August 2018 Al Sweigart
This page has materials for folks taking my two-hour tutorial, A Beginner's Guide to Tackling Recursion at PyOhio 2018 or following its video recording.
The Zen of Python, Explained
Fri 17 August 2018 Al Sweigart
The Zen of Python by Tim Peters are 20 guidelines for the design of the Python language. Your Python code doesn’t necessarily have to follow these guidelines, but they’re good to keep in mind. The Zen of Python is an Easter egg, or hidden joke, that appears if you run import this.
Python's Fake Increment and Decrement Operators
Mon 21 May 2018 Al Sweigart
In Python, you can increase the value of a variable by 1 or reduce it by 1 using the augmented assignment operators. The code spam += 1 and spam -= 1 increments and decrements the numeric values in spam by 1, respectively.
Other languages such as C++ and Java have the ++ and -- operators for incrementing and decrementing variables. (The name of C++ itself reflects this; the name is a tongue-in-cheek joke that indicates it's an enhanced form of the C language.) Code in C++ and Java could have ++spam or spam++. Python wisely doesn't include these operators; they are notoriously susceptible to subtle bugs.
Python Tuples are Immutable, Except When They're Mutable
Mon 05 February 2018 Al Sweigart
Before we can get a nuanced answer to "Are tuples mutable or immutable?", we need some background information.
Translate Your Python 3 Program with the gettext Module
Sat 20 December 2014 Al Sweigart
You've written a Python 3 program and want to make it available in other languages. You could duplicate the entire code-base, then go painstakingly through each .py file and replace any text strings you find. Fortunately, Python provides a solution with the gettext module.
Programming a Bot to Play the "Sushi Go Round" Flash Game
Wed 17 December 2014 Al Sweigart
This tutorial teaches how to write a bot that can automatically play the Flash game Sushi Go Round. The concepts in this tutorial can be applied to make bots that play other games as well.