I know we can overload behavior of instances of a class, e.g. -
class Sample(object): pass s = Sample() print s <__main__.Sample object at 0x026277D0> print Sample <class '__main__.Sample'> We can change the result of print s:
class Sample(object): def __str__(self): return "Instance of Sample" s = Sample() print s Instance of Sample Can we change the result of print Sample?
You can use a metaclass:
class SampleMeta(type): def __str__(cls): return ' I am a Sample class.' Python 3:
class Sample(metaclass=SampleMeta): pass Python 2:
class Sample(object): __metaclass__ = SampleMeta Output:
I am a Sample class. A metaclass is the class of class. Its relationship to a class is analogous to that of a class to an instance. The same classstatement is used. Inheriting form type instead from object makes it a metaclass. By convention self is replaced by cls.