1.3 Installing Python on Your Computer

Introduction

Before you can start coding in Python, you need to install it on your computer. In this section, we will cover:

• How to download and install Python on Windows, macOS, and Linux
• How to verify the installation
• Installing pip (Python’s package manager)
• Setting up the Python environment and running your first script

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

As you work through the following steps, feel free to navigate to this GeeksForGeeks link for more assistance.

1.3.1 Check If Python is Already Installed

Before installing Python, you could check if it is already installed on your computer. At times, this could be the case, especially with macs. Based on your operating system, follow the appropriate instruction below:

• 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

If Python is already installed, you can skip to 1.3.4 Running Python.
If Python is not installed, follow the steps below to install it.

1.3.2 Installing Python on Windows

Step 1: Download Python

1. Go to the official Python website: https://www.python.org/downloads/
2. Click the Download Python 3.x.x button (Python 3 is the latest version).

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 Python accessible from the command line).
3. Click “Install Now” and wait for the installation to complete.

Step 3: Verify the Installation

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

python --version

You should see something like:

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. Check by running:

python3 --version

If it shows a version lower than Python 3.7, you should 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:

/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 see an output like:

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 ensurepip --default-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 Python is installed, you can run it 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

>>> 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 however.

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!
If you did not get this working, do not fret. When we get PyCharm working, it should be easier.

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 how to install PyCharm in the next section, here are a few popular IDEs for developing code in Python.

Popular Python IDEs and Code Editors:

Summary

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

• Windows: To install, download Python from python.org, check Add to PATH, and install.
• macOS: Use Homebrew to install Python (brew install python).
• Linux: Install Python via apt (sudo apt install python3).
• Check installation using python --version.
• pip is Python’s package manager; install/upgrade it using pip install --upgrade pip.
• Run Python in two ways:
  Interactive Mode (REPL): Run python in the terminal.
  Running Scripts: Save code in a .py file and execute it.
• 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.