Functions

Define your own reusable mini-tools. Arguments, return values, defaults, and the rules that keep functions honest.

Foundations 6 lessons ~50 min

Lessons in this module

1. def — defining your own function · 8 min
   Make a custom 'formula' you can call from anywhere in your code.
2. Returning multiple values & unpacking · 6 min
   How to send back more than one thing — using tuples and dict returns.
3. Scope — where variables live · 7 min
   Local vs global, why your variable disappeared after the function ran, and how to do this safely.
4. lambda, map, filter — the functional shortcuts · 7 min
   Tiny one-line functions and a quick tour of map() and filter().
5. Modules and imports — using other people's code · 7 min
   import, from-import, aliases, and the difference between standard library and third-party.
6. Anatomy of a real script · 8 min
   How professional Python scripts are organised — imports, constants, functions, and the if __name__ block.