How do I create an instance of a nested class from within that class in Python?

Question

class ExampleClass():
    def Example(self):
        self.nestedinstance = self.NestedClass()
        self.nestedinstance.makenew()


    class NestedClass():
        def makenew(self):
            newclass = NestedClass()

ExampleClass().Example()

When I run the above code I get the exception: name 'NestedClass' is not defined

Is there a different way to do this with a nested class or have I done something wrong?

Answer 1

You ideally want to be using classmethods if creating a new instance, this is an example of how you'd do it:

class NestedClass():
    @classmethod
    def makenew(cls):
        newclass = cls()

Alternatively if you wanted to create an instance using the current instance (for example if you needed to pass in some arguments), then you can get the class by using type(self) or self.__class__.

class NestedClass():
    def makenew(self):
        newclass = type(self)()

Without knowing your use case though, this may not be what you're after.