3.3 Python IDEs — Integrated Development Environments

An Integrated Development Environment (IDE) is a software application that provides a complete set of tools for writing, running, and debugging programs in one place.

Core Components of an IDE

Key IDE Features

• Syntax Highlighting — displays keywords, variables, strings, and comments in different colours to improve readability and catch errors quickly.
• Code Completion (IntelliSense) — predicts and suggests function names, variables, and code snippets as you type, speeding up development.
• Error Detection — underlines or flags syntax errors before the program is even run.

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Python IDLE

IDLE (Integrated Development and Learning Environment) is the default IDE bundled with every standard Python installation from python.org. It is lightweight and ideal for beginners.

Two Modes of IDLE

1. Interactive Mode (Python Shell)

• Statements are typed and executed immediately, one at a time.
• Useful for quick calculations and testing small snippets.
• Prompt appears as >>>.

>>> print("Hello, World!")
Hello, World!

2. Script Mode (Editor)

• Open via File → New File in IDLE.
• Write a complete, multi-line program and save it with a .py extension.
• Run the entire script at once using Run → Run Module or pressing F5.

# hello.py
name = input("Enter your name: ")
print("Hello,", name)

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Popular Python IDEs

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Debugger in an IDE

A debugger is a tool that helps programmers find and fix errors (bugs) in their code. Key debugger features include:

• Breakpoints — pause execution at a specific line so you can inspect the program state.
• Step Over / Step Into — execute code one line at a time.
• Variable Inspection — view the current value of variables at any point during execution.
• Call Stack — see the sequence of function calls that led to the current point.

Using the debugger is a core skill for CS-11-C-07 — determining ways to debug Python code.

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