Recursion: introduction and binary trees
[latexpage] A recursive function is one that calls itself. We can illustrate this with the usual example: the factorial function. Before presenting the example, however, it's advisable to begin with…
Handling errors with exceptions
Input errors One of the most tedious jobs in writing code designed to be used by others is checking a user's input to make sure it's valid. As an example,…
Writing and reading Python objects – the pickle module
We've seen how to write and read text files. This is fine if you want to store the data in a human readable form or transfer the data to some…
Writing and reading text files
Writing and reading text files in Python is fairly straightforward. It's easiest to illustrate the process with an example. Here is some code that generates the 52 cards in a…
Overloading comparison operators
[latexpage] Overloading the six comparison operators works in a similar way to the overloading of arithmetic operators. The operators and their associated methods are: Default behaviour Before we try overloading…
Overloading arithmetic operators
[latexpage] We've seen that the usual arithmetic operators +, -, * and / can be used with Python's numeric data types, and that some of these operators also have meaning…
Single inheritance and the super() function: the basics
[latexpage] One of the cornerstones of OOP is the concept of inheritance. The idea is best illustrated with an example. Suppose we have a number of objects that all have…
Encapsulation and private data
Programmers used to other object oriented languages such as C++, C# or Java will be familiar with the idea of private data fields and methods within a class. These private fields…