Class methods, static methods, object methods in Python

Note: The following are public-premise, private methods can only be called inside the class, do not need to speak more.

1. Object methods

This method has a default parameter: Self, which represents the object of the instance

    def __init__ (self):         Print (" Initialize object ")

Class is not a direct call to an object method:

class User (object):     ' ZS '    def __init__ (self):         Print (" Initialize object ") of User. __init__ ()

This call throws an error: TypeError: __init__ () Missing 1 required positional argument: ' Self '

2. Class methods

The class method, as the name implies, can be called directly from the class name, or by an object instantiated by the class.

classUser (object): Name='ZS'    __pass= 1223def __init__(self):Print("Initializing Objects") @classmethod#Decorator    def changeName1(CLS): Cls.name='ls'        Print("method%s for class"% (CLS.__pass))

ChangeName1 is a class method, preceded by a decorator: @classmethod, and has a default parameter, the CLS is the class itself.

3. Static method

In fact, static methods can be understood as a special class method, which differs from the normal class method in two points:

(1) Different modifiers

(2) No default parameters

The rest is identical to the class method.

classUser (object): Name='ZS'    __pass= 1223def __init__(self):Print("Initializing Objects") @classmethod#Decorator    defchangeName1 (CLS): Cls.name='ls'        Print("method%s for class"% (CLS.__pass)) @staticmethoddefchangeName2 (): User.Name='ww'        Print("Static Methods") U=User () u.changename1 () user.changename1 () u.changename2 () user.changename2 ()

Summary: An object instantiated by a class can invoke all public methods inside the class, and the class can only invoke the class method and the static method (if it is a private method, it can only be called inside the class. ）

Class methods, static methods, object methods in Python