Functions

Documentation Index

Fetch the complete documentation index at: https://python.datalumina.com/llms.txt

Use this file to discover all available pages before exploring further.

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Building with functions

Functions are reusable blocks of code that do specific tasks. Instead of writing the same code multiple times, you write it once as a function and call it whenever needed. Think of functions like:

• A recipe you can follow multiple times
• A machine that takes input and produces output
• A named shortcut for complex operations

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Why use functions?

• Don’t repeat yourself: Write code once, use it many times
• Stay organized: Break complex programs into smaller pieces
• Fix bugs easier: Change code in one place, affects everywhere
• Test your code: Test each function separately

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What you’ll learn

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Real-world examples

Functions are everywhere in programming:

• print() - displays text (built-in function)
• len() - counts items (built-in function)
• calculate_tax() - your custom function
• send_email() - your custom function

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Let’s begin!

Start by learning how to create your first function.