Найти похожее

https://anthony-zhang.me/blog/python-bound-methods/ when & why we use @#staticmethod

@#classmethod vs @#staticmethod vs "plain" methods What's the difference? class MyClass: def method(self): """ Instance methods need a class instance and can access the instance through self. """ return 'instance method called', self @classmethod def classmethod(cls): """ Class methods don't need a class instance. They can't access the instance (self) but they have access to the class itself via cls. """ return 'class method called', cls @staticmethod def staticmethod(): """ Static methods don't have access to cls or self. They work like regular functions but belong to the class's namespace. """ return 'static method called' # All methods types can be # called on a class instance: »> obj = MyClass() »> obj.method() ('instance method called', <MyClass instance at 0x1019381b8>) »> obj.classmethod() ('class method called', <class MyClass at 0x101a2f4c8>) »> obj.staticmethod() 'static method called' # Calling instance methods fails # if we only have the class object: »> MyClass.classmethod() ('class method called', <class MyClass at 0x101a2f4c8>) »> MyClass.staticmethod() 'static method called' »> MyClass.method() TypeError: "unbound method method() must be called with MyClass " "instance as first argument (got nothing instead)"

# @classmethod vs @staticmethod vs "plain" methods # What's the difference? class MyClass: def method(self): """ Instance methods need a class instance and can access the instance through self. """ return 'instance method called', self @classmethod def classmethod(cls): """ Class methods don't need a class instance. They can't access the instance (self) but they have access to the class itself via cls. """ return 'class method called', cls @staticmethod def staticmethod(): """ Static methods don't have access to cls or self. They work like regular functions but belong to the class's namespace. """ return 'static method called' # All methods types can be # called on a class instance: »> obj = MyClass() »> obj.method() ('instance method called', <MyClass instance at 0x1019381b8>) »> obj.classmethod() ('class method called', <class MyClass at 0x101a2f4c8>) »> obj.staticmethod() 'static method called' # Calling instance methods fails # if we only have the class object: »> MyClass.classmethod() ('class method called', <class MyClass at 0x101a2f4c8>) »> MyClass.staticmethod() 'static method called' »> MyClass.method() TypeError: "unbound method method() must be called with MyClass " "instance as first argument (got nothing instead)" #classmethod#staticmethod

goo.gl/QkvD2L #staticmethod #Classmethod

https://docs.python.org/3/library/functions.html#staticmethod #staticmethod(function) Return a #static method for function. A static method does not receive an implicit first argument. To declare a static method, use this idiom: class C: @staticmethod def f(arg1, arg2, ...): ... The @staticmethod form is a function decorator – see the description of function definitions in Function definitions for details. It can be called either on the class (such as C.f()) or on an instance (such as C().f()). The instance is ignored except for its class. Static methods in Python are similar to those found in Java or C++. Also see classmethod() for a variant that is useful for creating alternate class constructors. For more information on static methods, consult the documentation on the standard type hierarchy in The standard type hierarchy. class str(object='') class str(object=b'', encoding='utf-8', errors='strict') Return a str version of object. See str() for details. str is the built-in string class. For general information about strings, see Text Sequence Type — str.