Working with Objects

Learning Goals

• describe an object
• access information from one object in another object

Structure

5 min - Warm Up
20 min - What is an object? 5 min - Break
20 min - Objects upon Objects upon Objects 5 min - Wrap Up

Vocabulary

• Object
• Instance Methods

Warm Up

• What is an object?
• How do you access the state of an object?
• How do you access an object from within another object?

What is an Object

Abstraction

How we represent real world things and processes using code.

Classes

We build objects by using classes. A class can be thought of as an object blueprint.

Independent Practice

Make a table class that takes two arguments - type & material Create 3 different table objects

dining_table = Table.new("dining", "wood")

Make a seat class that takes two arguments - type & material
Create 3 different table objects

armchair = Seat.new("stool", "metal")

Turn & Talk

How did you make objects? What charactertistics does your table object have? What characteristics does your seat object have?

** break **

Objects upon Objects upon Objects

Sets of Objects

You’ve made table and seat classes. How do we interact with them? Let’s build out a furniture class.

furniture = Furniture.new

Now I want to make it so my furniture holds a collection of table objects and can give us information about them.

• What are our options for holding collections?
• How can we add a table to that collection?
• What if we want to return a collection of types of tables?

Independent Practice

Lets add the same functionality from above using seats.

We want our furniture to hold a collection of seat objects.

• Create a collector to hold your seats
• Build a method that adds a seat to that collection
• Build a method that returns a collection of the materials of our seats.

Extra Challenges:

• Make it so our material collection returns without any duplicates
• Build a method that returns the most common type of seat
• Build a method that sorts the seat materials alphabetically

Turn & Talk

Code Share: Share your implementation.

• What methods did you build?
• What were they named?
• How did they work?

Wrap Up

• What is an object?
• How do you access an object from within another object?
• Why might you want to access an object from within another object?