Python Made Easy: A First Course in Computer Programming using Python

Getting Started

The aim of this book is to provide a first course in the use of a methodical and effective approach to the development of computer programs using the Python Programming Language.

Chapters have been deliberately kept short with a learn by doing approach. Along the way, you’ll find various video tutorials and demonstrations you can access using the various links throughout the book.

Chapter by chapter, we’ll explore the ins and outs of Python with illustrations, worked examples, lab exercises and projects for you to complete yourself. For this purpose, we’ve included all the source code for this book in the following repository:

elluminetpress.com/python2

Have Fun!

What is Python

Python is a high-level programming language created by Guido van Rossum and first released in 1991. The name Python was inspired by Guido’s love for the British comedy series Monty Python’s Flying Circus.

Python emphasizes code readability and aims to provide a clear and concise syntax, making it easier for programmers to express concepts and ideas in fewer lines of code compared to other programming languages. There is also a comprehensive library that provides a wide range of built in modules and functions for common programming tasks. This philosophy encourages the reuse of existing code and reduces the need for developers to rely heavily on third-party libraries for basic functionalities. Over the years, Python has attracted a large community of developers who contribute to its extensive ecosystem of third-party libraries and frameworks, further expanding its capabilities.

Python is designed to be a versatile language and is widely used in web development, data analysis, artificial intelligence, scientific computing, and automation.

Installing Python

In this section, we’ll take a look at how to install the python interpreter and development environment.

Python has multiple versions available, such as Python 2.x and Python 3.x. It is recommended to install the latest stable version, which is Python 3.x. Python 2.x is no longer actively supported, and most new projects and libraries are designed for Python 3.x.

You can install python on Windows, Mac, or linux.

Install on Windows

In our lab, we’re using windows workstations, so we’ll need to install the Python Development Environment for Windows.

Open your web browser and navigate to the following website:

www.python.org/downloads/windows

From the downloads page, select the ‘executable installer’ of latest stable release.

Click ‘run’ when prompted by your browser. Or click ‘python-x.x.x-amd64.exe’ if you’re using Chrome.

Once the installer starts, make sure ‘add python 3.x to path’ is selected, then click ‘customize installation’ to run through the steps to complete the installation.

Make sure you select all the tick boxes for all the optional features. Click ‘next’.

Make sure ‘install for all users’ is selected at the top of the dialog box. Click ‘install’ to begin.

Click ‘disable path length limit’ to make sure Python runs smoothly on Windows and allow long file names.

Click ‘close’ to finish the installation.

You’ll find the Python Development Environment (IDLE) and the Python interpreter, in the Python folder on your start menu.

Install on MacOS

To install Python 3 with the Official Installer, open your web browser and navigate to the following website

www.python.org/downloads/macos

Click download python.

You’ll find the package in your downloads folder. Double click on the package to begin the installation

Run through the installation wizard. Click ‘continue’.

Once the installation is complete, you’ll find python in the applications folder in finder, or on the launch pad.

Install on Linux

If you are running a linux distribution such as Ubuntu or have a Raspberry Pi, you can install python using the terminal. You’ll find the terminal app in your applications. You can also press Control Alt T on your keyboard.

At the terminal command prompt, type the following commands. Press enter after each line.

sudo apt update

sudo apt upgrade

Type the following command to install Python.

sudo apt install python3 -y

Once the Python is installed, we need to install IDLE, the development environment. To do this, type the following command at the prompt

sudo apt-get install idle3 -y

Once installed, you’ll find IDLE in your applications.

Or you can type the following command at the prompt

idle

Setting up a Development Environment

A good development environment enhances productivity by providing features such as code editing, debugging, and testing capabilities.

There are several code editors and Integrated Development Environments (IDEs) available for Python programming. Once you have installed the python interpreter as discussed above, you should install a code editor or IDE. What you choose is personal preference and depends on the specific requirements of your project.

Try a few difference ones until you find the one that suits your needs the best.

Code Editor vs IDE

A code editor is a lightweight tool focused primarily on editing code. It provides features such as syntax highlighting, code completion, and basic code formatting. Some popular code editors are Visual Studio Code and Sublime Text.

An IDE is a comprehensive software suite that combines a code editor with additional tools and features specifically designed for software development. In addition to code editing capabilities, IDEs typically provide features like debugging, code refactoring, project management, and version control integration. Examples of popular IDEs include PyCharm, IDLE and Eclipse.

You should also consider an interactive computing environment. This is a software environment that allows you to interactively write and execute code while providing immediate feedback and results. Within this environment you can write code, run it, and see the output in real-time, facilitating an iterative and exploratory approach to programming.

Jupyter Notebook is a popular interactive computing environment that allows you to create and share documents containing live code, visualizations, and explanatory text.

Visual Studio Code (VS Code)

Visual Studio Code is a lightweight and highly customizable code editor developed by Microsoft.

code.visualstudio.com

It has excellent Python support with features such as IntelliSense which provides context-aware suggestions for functions, methods, variables, and modules as you type, helping you write code faster and with fewer errors.

VS Code also offers debugging tools and a wide range of extensions that enhance Python development experience.

PyCharm

PyCharm is a powerful IDE specifically designed for Python development. You can download the software here:

www.jetbrains.com/pycharm

It provides advanced features like intelligent code completion, refactoring tools, debugging, testing frameworks integration, and support for web development frameworks like Django and Flask.

PyCharm is available in both free Community Edition and paid Professional Edition versions.

Sublime Text

Sublime Text is a popular cross-platform code editor known for its speed and simplicity. You can download the software here:

www.sublimetext.com

It supports Python development through various community-developed packages. Sublime Text offers a distraction-free writing mode, multiple cursors, and powerful search and navigation features.

IDLE

IDLE (Integrated Development and Learning Environment) is a basic Python IDE that comes bundled with the Python installation. It provides a simple and beginner-friendly environment for writing and running Python code.

While IDLE is a convenient option for beginners or when you need a lightweight and straightforward development environment, however it lacks some advanced features and customization options compared to other IDEs. As your Python programming skills and projects become more complex, you may want to explore other IDEs mentioned earlier to leverage additional functionalities and tools for efficient development.

Jupyter Notebook

Jupyter Notebook is an open-source web-based interactive computing environment that allows users to create and share documents called notebooks. To install jupyter notebook, open the command prompt, then run the following command.

pip install jupyter

Run the following command to run Jupyter Notebook.

jupyter notebook

Notebook will pop up in your web browser. If it doesn’t open your browser and navigate to

http://localhost:8888/tree

You’ll land on the jupyter page.

Anaconda is a popular Python distribution that comes bundled with Jupyter Notebook. You can download this here.

www.anaconda.com/products/individual

Once you download the installer, run through the setup process.

You’ll find Anaconda Navigator, and Anaconda Spyder. Anaconda Navigator allows you to create and manage isolated Python environments, switch between different versions of Python, and install/uninstall packages. Spyder is an integrated development environment specifically designed for scientific Python programming and data analysis. It provides a powerful and feature-rich environment for writing, testing, and debugging Python code.

Summary

Python is a high-level programming language created by Guido van Rossum in 1991, known for its readability and concise syntax.

Python has a comprehensive library that includes built-in modules and functions for common programming tasks, reducing the need for third-party libraries.

Python is versatile and widely used in web development, data analysis, artificial intelligence, scientific computing, and automation.

Code editors such as Visual Studio Code and Sublime Text offer lightweight tools for editing code.

Integrated Development Environments (IDEs) such as PyCharm, IDLE, and Eclipse provide additional features like debugging, code refactoring, and project management.

Visual Studio Code is recommended in the book, with excellent Python support, debugging tools, and a wide range of extensions.

PyCharm is a powerful IDE specifically designed for Python development, available in both free and paid versions.

Sublime Text is a popular cross-platform code editor with support for Python development through community-developed packages.

IDLE is a basic Python IDE bundled with the Python installation, suitable for beginners or lightweight development but lacking advanced features.

Jupyter Notebook is an open-source web-based interactive computing environment that allows users to create and share documents called notebooks.

Anaconda is a popular Python distribution that comes bundled with Jupyter Notebook.

Python Basics

Python is an interpreted programming language, meaning the source code is executed line by line at runtime without the need for prior compilation into machine code.

When you run a Python program, the interpreter translates the source code into bytecode which is then executed by the Python Virtual Machine (PVM). The PVM is responsible for executing the bytecode and managing the memory, objects, and other runtime aspects of the Python program.

Python’s appeal lies in its simplicity and readability. The syntax emphasizes code clarity, using indentation rather than traditional braces or keywords to delimit blocks of code.

For this chapter, you’ll need to download the source code files from:

elluminetpress.com/pyb

You’ll also find various video demos and tutorials.

Language Syntax

Syntax refers to the set of rules and structure that define the correct arrangement and usage of elements in a programming language. The rules specify how the code should be structured, including the order and placement of keywords, operators, variables, and other elements. Adhering to the syntax rules is crucial because even small deviations can result in code that produces syntax errors.

Reserved Words

Reserved words, also known as keywords, are words that have special meaning and are reserved for specific purposes. These words cannot be used as variable names or other identifiers because they are already used by the language itself.

Indentation

Python uses indentation to define code blocks instead of using braces or keywords like begin and end as in other languages. Code blocks are usually indented using spaces or tabs (eg use four spaces per indentation level).

Consistent indentation is crucial in Python because it determines the grouping and hierarchy of code. It is important to note that mixing spaces and tabs for indentation can lead to errors, so it’s best to choose one and stick to it. In the example below, notice how the indentation is used to define the code blocks within the greet function.

The lines of code inside the if and else blocks are indented, indicating that they are part of those blocks.