Search for tag: "fractions"

Lesson 24.2 The isinstance Function

In this video, we show that we can solve the problem of strict typing by using the isinstance function. This function will be our preferred way for enforcing preconditions going forward.

From  Hannah Lee on November 12th, 2020 30 plays

Lesson 24.1 Strict Typing

Whenever we have enforced preconditions, we have always used the type function. In this video we show why that is a problem, particularly when we want to use an object argument that is a subclass of…

From  Hannah Lee on November 12th, 2020 27 plays

Lesson 23.5 Mixed-Type Operators

Operator overloading allows us to redefine the meaning of + or * on objects of our class. But sometimes we want to mix together types like a fraction and integer. In this video we show that it is…

From  Hannah Lee on November 8th, 2020 39 plays

Lesson23.4 The is Operator

As we saw in the previous video, we cannot trust == if we need to test if two variables refer to the same object folder. In this video we show an alternative operator is, which is safe to use because…

From  Hannah Lee on November 8th, 2020 30 plays

Lesson 23.3 Object Equality

Previously when we compared objects, we compared them attribute-by-attribute. That is because the meaning of == on objects is less clear. As we show in this video, that is because equality (and the…

From  Hannah Lee on November 8th, 2020 44 plays

Lesson 23.1 The Principle of Abstraction

In this video we introduce the principle of abstraction, which is simply hiding unnecessary details about a class from the user of a class. However, there are many different ways to do that, which is…

From  Hannah Lee on November 8th, 2020 40 plays