[Week 3] Encapsulating code

Summary

Now that we’ve started to practice mastering the state of objects (keeping track of their properties), we will work on making our code more efficient.

In-class code

1. Basic Pygame Template
2. Basic stick figure

Important Concepts

1. Functions

   • A code block which packages the code and provides a shortcut to executing the code
   • The code below shows how to pass information in, how to get information out
   • important: remember that scope means what variables can be “seen” inside and outside the function

Example:

def hello_x(x):
    y = "hello {}".format(x)
    return y
y = hello_x("world")
print(y)

2. Dictionaries

   • A python variable type that allows you to map keys to values

Example

bob = dict()
bob['name'] = 'bob'
bob['species'] = 'turtle'

3. Encapsulation.

   • The packaging of code to be reused later

   • Example: if we have multiple objects, and we want to make them bounce off walls,

     then we could either write the wall bouncing code for each object, or write the code once and use a function to apply it to each object.

Homework

See the slides for more information. The basic gist: practice dictionaries and functions.

Slides