Python Setup

Need for Python Installation

To build software or applications using Python, two components are essential:

1. Python Interpreter

• The interpreter reads and executes Python code.
• Without it, your computer cannot understand or run .py files.

2. IDE (Integrated Development Environment)

An IDE provides a user-friendly workspace where you can:

• Write code
• Test and debug programs
• Run Python scripts efficiently

Popular IDEs for Python

• Python IDLE – comes pre-installed with Python
• PyCharm (JetBrains) – most widely used and feature-rich IDE for Python
• VS Code – lightweight and highly customizable
• Anaconda (Spyder / Jupyter) – preferred for data science

Installing Python

Step 1: Check if Python is Already Installed

Open Command Prompt (CMD) and run:

python --version
python3 --version

If you see an error like this, then Python is not installed:

Python was not found; run without arguments to install from the Microsoft Store...

Step 2: Download Python

1. Visit the official website: https://www.python.org/downloads/

2. Download the latest stable Python version (e.g., Python 3.13.5).

3. Choose the correct installer:

   • Windows 64-bit → Recommended for most systems (Intel i5/i7, AMD Ryzen)
   • ARM version → Only if your device specifically supports ARM

Check the option "Add Python.exe to PATH" during installation. This ensures Python commands work in the terminal.

Step 3: Verify Installation

Open Command Prompt / Terminal and run:

python --version

or

python3 --version

If installed correctly, it will display something like:

Python 3.13.5

Running Python Code

You can run Python programs in the following ways:

1) Python Interactive Shell (REPL)

Start Python directly in the terminal:

> python
>>> print("Hello")
Hello

This mode is great for testing small code snippets.

2) Running Python Files (.py)

For multi-line code:

1. Open an editor or IDE
2. Write your Python code
3. Save the file with the .py extension, e.g., Demo.py

Navigate to the folder in your terminal:

> cd path/to/folder
> ls    # show files

Run the script:

> python Demo.py

Output:

Hello

Importance of the .py File Extension

The .py extension plays a vital role in Python programming. It identifies a file as a Python script and ensures that tools, interpreters, and IDEs handle the file correctly. Without this extension, the Python interpreter and development tools cannot treat the file as executable Python code.

1. Recognized as Python Source Code

Files ending with .py are automatically understood by the Python interpreter as Python scripts. This allows commands like:

python script.py

to execute the file successfully.

2. Full IDE Support (Syntax Highlighting, Debugging, Intellisense)

IDEs such as PyCharm, VS Code, and IDLE depend on the .py extension to enable:

• Syntax highlighting
• Code suggestions
• Error detection
• Debugging tools

A file saved as .txt will not receive these features because the IDE does not treat it as Python code.

3. Modules and Imports Work Only With .py Files

Python’s import system recognizes only .py files as modules. For example:

import utils

will work only if the file is named:

utils.py

If it is utils.txt, Python cannot import it.