Python is a high-level, general-purpose programming language. It is notorious for having a very simple "pseudocode-like" syntax that places emphasis on readability and expressiveness. This not only makes code simpler to write but also easier to maintain. Additionally, it features a vast standard library that is augmented by an even larger array of third-party libraries. These are all developed and supported by Python's very active community.
Development is also faster in Python, as it is an interpreted language. This means that the instructions are interpreted at runtime and there's no need to pre-compile the program into machine language instructions. This makes for quick prototyping and experimentation. Python's interpreted nature, along with its dynamic typing system, are what really set it apart from languages such as Java or C++.
Python also supports multiple paradigms, such as the following:
Object-oriented programming
Functional programming
Imperative programming
Procedural programming
This versatility, coupled with Python's ability to run on all operating system platforms from Windows and GNU/Linux to macOS, have led to its popularity. As a matter of fact, today, Python comes built-in into most GNU/Linux distributions as well as macOS.
Python can be applied for writing automation scripts, machine learning, scientific computation, big data, web applications, GUI programming, IoT devices—just about anything. It's a multipurpose language and is easy to extend. Due to this, Python has been adopted by tech companies such as Google (for YouTube), Uber, Facebook, and Mozilla, further ensuring its support and development.
In this chapter, we will write our first Python program and play with the interpreter through the use of the Python interactive shell. We will also take a look at the different ways of running a Python program.
Before we move on to getting our hands dirty, we'll take a brief look at the history of Python. Out there in the wild, you'll find codebases that use Python 3 or the older Python 2. The two are very similar. Generally, a lot of the code written for Python 3 will run on Python 2 and vice versa, but this should not be practiced as there are a few syntactic differences that can bring about issues. However, the majority of the differences between the two are under the bonnet.
Currently, support still runs for Python 2, but Python 3 is the only one in active development, meaning any new features brought to the language are only developed for Python 3. Additionally, the majority of commonly used third-party libraries have now ported to Python 3 and are withdrawing development for their Python 2 versions. For this reason, we will be using Python 3.6 for all of the examples in this book.