Python Data Structures and Algorithms

Variables and expressions

To translate a real-world problem into one that can be solved by an algorithm, there are two interrelated tasks. Firstly, select the variables, and secondly, find the expressions that relate to these variables. Variables are labels attached to objects; they are not the object itself. They are not containers for objects either. A variable does not contain the object, rather it acts as a pointer or reference to an object. For example, consider the following code:

Here we have created a variable, a, which points to a list object. We create another variable, b, which points to this same list object. When we append an ...