Function Recipes

Recipes for writing and using your own functions:

1. Write Your Own Function: I want to easily reuse a particular calculation multiple times, with different givens.

2. Make Arguments Optional: I want my code to decide what to do based on the circumstances.

3. Execute Conditionally: I want my code to decide what to do based on the circumstances.

4. Safety-Check Arguments: I want to make my function robust against incorrect or unexpected arguments.

5. Factor Out Subfunctions: I want to break a complicated calculation into pieces to keep it manageable.

6. Use Global Variables (Sparingly!): I need to get values deep into a function or subfunction, and passing them via arguments is tedious.

7. Run or Import From a Script: I want to write a script that I can run, and I also want to use functions it defines in the console or other scripts.