This article is a quick guide on how to create and run your own open-source project. Specifically, it assumes it will be a Python project, although many of the things covered here can be applied to other types of project.

This isn’t a guide on how to set up a GitHub account and commit your first source files. Instead, it focusses on the wider whys and hows of open source development, and will hopefully help you to avoid the common pitfalls.

Why do it?

People create open-source software for many different reasons.

Quite often, a developer will decide to create a piece of…

What I learned from writing three Python books in a year

Over the past year or so, I have written three e-books on various topics in Python programming. Although I certainly don’t consider myself to be an expert on self-publishing, I have learned a bit in this time, so I will share it here. I hope you might find it useful.

This article covers four stages:

• Choosing and researching the topic.
• Writing the manuscript.
• Making it available for sale.
• Generating sales.

I have found the whole process takes me about 3 months, if I put most of my hobby time…

Process images in 3 lines of Python

Pillow is a versatile and popular Python imaging library. The ImageEnhance module is a particularly useful module within Pillow. It can be used to adjust colour, contrast, brightness and sharpness in a few simple lines of code.

_Enhance interface

Each image enhance function is implemented as an object that implements the _Enhance interface. The interface provides a single method:

enhance(factor)

For example, the ImageEnhance.Brightness class controls the brightness of an image, It has an enhance method that it inherits from _Enhance.

factor is a number that controls the effect. For example, for Brightness a factor…

Easy animation with generativepy

generativepy makes it very easy to create animated GIFs. This can be done with a simple script, and usually results in a fairly well optimised GIf file.

The gif module makes use of the gifsicle application. This can be downloaded for free, and must be installed on your system in order for the gif module to work.

GIF images

GIF (Graphics Interchange Format) is a bitmap image format that was developed in the 1980s for transferring images over networks. …

Deriving new functions with functools

Functional programming is a paradigm in which functions form the fundamental building blocks.

It should be no surprise that functional programming includes several techniques for deriving new functions from existing functions. This is analogous to object oriented programming, where classes are the building block, and we have various ways to derive new classes from existing ones (inheritance and composition, for example). In both cases, the aim is the same — to reuse existing code (following the DRY principle, don’t repeat yourself).

Partial application is one such technique.

What is partial application?

Here is a function that returns the value…

It is, of course, vital to test software. There are various ways to test software, including:

• Testing that the individual software components of the system work correctly. This can include anything from testing an entire sub-system, or testing individual modules.
• Testing the whole system — this can take the form of integration testing, end-to-end testing, and functional testing, etc, that each emphasises different aspects of system testing.
• More specialised forms of testing — for example, acceptance tests are often used as part of a development contract to prove that the software is fit for purpose, performance testing proves that the…

Simple implementations of the List and Maybe monads.

In the article on the Failure monad we looked at a simple definition of what a monad is:

A monad is a design pattern that allows us to add a context to data values, and also allows us to easily compose existing functions so that they execute in a context aware manner.

In this article we will look at two other common monads:

• List monads
• Maybe monads

List monads

A List monad allows us to process lists of values, without cluttering our code with looping constructs.

How a List monad is used

As with the Failure monad, our List monad…

A simple implementation of the Failure monad.

Image by Safijc

Monads have a reputation for being difficult to understand, but in this article we will look at a simple Python implementation of a simple monad. This will hopefully give some insight into what monads are all about.

What is a monad

In functional programming, we use functions as our primary building block, and function composition as one of the basic ways to structure our code. By function composition we mean functions that call other functions, like this:

y = str(neg(int(x)))

This composed function takes a string, converts it to an integer, negates it, and…