Video on Inheritance

Please watch the first 5 minutes of this video. It contains detailed information about inheritance in Python.

Conclusions

• Inheritance is the ability to define a new class that is a modified version of an existing class.

• This relationship between classes—similar, but different—is one of the reasons to use inheritance, because otherwise the code would be duplicated. To define a new class that inherits from an existing class, you put the name of the existing class in parentheses. When a new class inherits from an existing one, the existing one is called the parent and the new class is called the child.

• It's possible that, if used excessively, inheritance can make programs difficult to read. When a method is called, it is sometimes not clear where to find its definition. The relevant code may be spread across several files.

• In some cases, though, you can express a child class as being a type of the base class. For example, a Car is a type of a Vehicle. For cases like this, inheritance reflects the natural structure of the concepts, which makes the design easier to understand.