1.3 Installing Python on Your Computer

Introduction

Before you can start writing some Python code, you would need to install some software on your computer.

In this section, we will cover the following subjects:

1. How to download and install the Python interpreter on a system.
2. How to verify the Python installation
3. How to install Python’s package manager – pip
4. Setting up a Python environment and running your first script

By the end of this section, you should have Python fully installed and ready to use.

While you navigate the course content, feel free to also refer to additional material on the free content link at GeeksForGeeks. This provides you with an alternative perspective to the content in this course.

1.3.1 Check If Python Interpreter is Already Installed

You  can check whether Python has already been installed on the system that you intend to use for the course.

In certain instances, the interpreter could already exist based on the platform, such as with macOS systems.

To confirm if the interpreter exists, use the appropriate instruction from below based on your operating system:

• Windows: Open Command Prompt (cmd) and type:

  • python --version
    

    or

    python3 --version
    

• macOS/Linux: Open Terminal and type:

  • python3 --version
    

    If Python is installed, you will see an output like:

    Python 3.10.5
    

1.3.2 Installing Python on Windows

Step 1: Download Python

1. In your preferred browser, navigate to the official Python website: https://www.python.org/downloads/
2. Click the button – Download Python 3.x.x (Python 3 is the latest version at this writing).

Step 2: Run the Installer

1. Locate the downloaded file (python-3.x.x.exe) and double-click it to start the installation.
2. Important: On the first screen, check the box “Add Python to PATH”. This makes the Python interpreter accessible from the command line.
3. Click “Install Now” and wait for the installation to complete.

Step 3: Verify the Installation

After installation, open the Command Prompt (cmd) and type in the following:

python --version

You should see something similar to the printout below:

Python 3.10.5

1.3.3 Installing Python on macOS

Step 1: Check If Python is Installed

Most macOS versions come with Python pre-installed. Confirm this by running the following line:

python3 --version

If it prints out a version lower than Python 3.7, you would need to install the latest version.

Step 2: Install Python Using Homebrew (Recommended)

Homebrew is a package manager for macOS that makes installation easier.

1. First, install Homebrew (if not already installed) by running the following:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

2. Install Python using Homebrew:

brew install python

3. Verify the installation:

python3 --version

You should then see the following output:

Python 3.10.5

1.3.4 Installing Python on Linux (Ubuntu/Debian)

Most Linux distributions come with Python pre-installed. To check:

python3 --version

Installing Python on Ubuntu/Debian

If Python is not installed or needs an update, use apt:

sudo apt update
sudo apt install python3

Installing Python on Fedora (Red Hat-based)

Use dnf:

sudo dnf install python3

Verify installation by running:

python3 --version

1.3.5 Installing pip (Python Package Manager)

pip allows you to install external Python libraries.
Python 3.x comes with pip pre-installed, but you can manually install or upgrade it:

• Check if pip is installed:

pip --version

• If pip is not installed, install it using:

python -m pip install --upgrade pip

• Upgrade pip to the latest version:

pip install --upgrade pip

Now you can install packages like NumPy, pandas, Flask, etc.

Example: Installing NumPy

pip install numpy

1.3.6 Running Python

Once you have successfully installed the Python interpreter, you can run it directly in two ways:

Running Python in Interactive Mode (REPL) – Optional

Python provides an interactive shell (Read-Eval-Print Loop, REPL) where you can type commands and get instant results.

Open Command Prompt (Windows) or Terminal (macOS/Linux) and type:

python

or

python3

You will see the Python prompt (>>>), indicating that Python is ready to execute commands.

Example: Running Python Commands in REPL
Try the scripts below

>>> print("Hello, Python!")
Hello, Python!
>>> 2 + 3
5
>>> exit()  # Type 'exit()' to leave the Python shell

This is how you use Python interactively. But we shall not use this approach.

Running a Python Script

Python scripts are files with the extension .py . This indicates that the file contains Python code.

Example: Creating and Running a Python Script
Open a text editor (Notepad, VS Code, or PyCharm – Next Section).
Type the following code and save the file as hello.py:

print("Welcome to Python Programming!")

Open Command Prompt/Terminal, navigate to the file’s location, and run:

python hello.py

Output:

Welcome to Python Programming!

Terrific! you have successfully written and executed your first Python script!

1.3.7 Setting Up an IDE (Optional)

While Python can be run in the terminal, using an Integrated Development Environment (IDE) improves coding efficiency.

While we shall cover the installation of PyCharm in the next section, we will discuss below the available IDEs for writing Python code.

Popular Python IDEs and Code Editors:

Summary

Here is a summary of what we have discussed in this section.

1. Windows: To install, download Python from python.org, check Add to PATH, and install.
2. macOS: Use Homebrew to install Python (brew install python).
3. Linux: Install Python via apt (sudo apt install python3).
4. Check installation using python --version.
5. pip is Python’s package manager; install/upgrade it using pip install --upgrade pip.
6. Run Python in two ways:
   • Interactive Mode (REPL): Run python in the terminal.
   • Running Scripts: Save code in a .py file and execute it.
7. Using an IDE like PyCharm, VS Code, or Jupyter Notebook enhances coding experience.

What’s Next?

Now that you have installed Python, let’s move to Chapter 1.4: Setting Up PyCharm as Your IDE, where we will configure PyCharm for a professional coding experience.