What are class methods and static methods?

Can you explain the difference between class methods and static methods?

Sure! Class methods are methods that belong to the class rather than an instance of the class. They can modify class state that applies across all instances. Static methods, on the other hand, do not access or modify class or instance state. They are utility functions that belong to the class's namespace.

Can you give me an example of each?

Of course! Here's a simple example in Python:

class MyClass:
    class_variable = 0

    @classmethod
    def class_method(cls):
        cls.class_variable += 1
        return cls.class_variable

    @staticmethod
    def static_method(x, y):
        return x + y

In this example, class_method modifies the class variable, while static_method simply adds two numbers.

When would I use a static method instead of a class method?

You would use a static method when you need a function that doesn't need to access or modify class or instance data. It's useful for utility functions that are related to the class but don't require any context from it.

Are there any performance differences between the two?

Generally, static methods can be slightly faster since they don't have to deal with the class or instance context. However, the difference is usually negligible unless you're calling them in a performance-critical loop.