Graphics

Graphics package is not standard Python
Applications Programming Interface (API)

Review of Functions

Reasons to Use:
1. Organization & Design—Divide and Conquer
2. Replace Duplicated Actions—karaoke examples

Parameters
1. Formal and actual
2. Must pass everything you need (unless using global variable which you shouldn't)

Global variables
1, Very bad programming style
2. Don't use in this course
3. Typically, used only for very large data structures you don't want to copy

Returns
1. Last line of function & only one per function
2. In Python, can return single or multiple values as tuples
3. Used to change values

Aside 1: Tuples
Like list but immutable and uses parentheses rather than brackets

Aside 2: Update operators
1. +=, -=, *=, /=, and %=
2. Examples—x += 1 or y *= y + 2
3. Fully evaluate right side before applying to update
E.g., x *= 2 + 3 IS x = x * (2 + 3), NOT x = x * 2 + 3

Homework: Energy Density Calculator with GUI