Django has a Paginator class that comes built in and ready to use. Perhaps you have a project on the go, and you’d like to try out the pagination implementations in the following sections with your app as your base. No problem! However, if you want to follow the step-by-step code examples in this tutorial, then you can download the source code for the Django Python wiki project from the Real Python materials repository: This wiki project contains an app […]

When you’re automating some task, for example packaging your application for Docker, you’ll often find yourself writing shell scripts. You might have a bash script to drive the packaging process, and another script as an entry point for the container. As your packaging grows in complexity, so does your shell script. Everything works fine. And then, one day, your shell script does something completely wrong. That’s when you realize your mistake: bash, and shell scripting languages in general, are mostly […]

When you look at an image, you see the objects and people in it. However, when you read an image programmatically with Python or any other language, the computer sees an array of numbers. In this tutorial, you’ll learn how to manipulate images and perform basic image processing using the Python Pillow library. Pillow and its predecessor, PIL, are the original Python libraries for dealing with images. Even though there are other Python libraries for image processing, Pillow remains an […]

Look back at how you added the Python timer to the example above. Note that you need at least one variable (tic) to store the state of the Python timer before you download the tutorial. After studying the code a little, you might also note that the three highlighted lines are added only for timing purposes! Now, you’ll create a class that does the same as your manual calls to perf_counter(), but in a more readable and consistent manner. Throughout […]

Invented over half a century ago, the hash table is a classic data structure that has been fundamental to programming. To this day, it helps solve many real-life problems, such as indexing database tables, caching computed values, or implementing sets. It often comes up in job interviews, and Python uses hash tables all over the place to make name lookups almost instantaneous. Even though Python comes with its own hash table called dict, it can be helpful to understand how […]

If you need to process a large JSON file in Python, it’s very easy to run out of memory. Even if the raw data fits in memory, the Python representation can increase memory usage even more. And that means either slow processing, as your program swaps to disk, or crashing when you run out of memory. One common solution is streaming parsing, aka lazy parsing, iterative parsing, or chunked processing. Let’s see how you can apply this technique to JSON […]

Like many other programming languages, Python supports object-oriented programming. At the heart of Python’s object-oriented capabilities, you’ll find the class keyword, which allows you to define custom classes that can have attributes for storing data and methods for providing behaviors. Once you have a class to work with, then you can start creating new instances or objects of that class, which is an efficient way to reuse functionality in your code. Creating and initializing objects of a given class is […]