Python Learning note __7.1 using __slots__

# This is a learning note for the Liaoche teacher Python tutorial

1 , binding methods for instances

# define a function

>>> def set_age(self, Age): # define a function as an instance method

... self.age = age

# Bind method for instance

>>> from types import Methodtype

>>> s.set_age = methodtype (set_age, s) # Bind a method to an instance

# for Class binding methods

>>> student.set_ Age = set_ Age # Assign a value directly to the class binding method

Attention:

• A method that binds to an instance that does not work for another instance

• Dynamic binding allows us to dynamically add functionality to class while the program is running, which is difficult to implement in a static language.

2 , restriction Properties

Python allows you to define a special __slots__ variable when defining a class to limit the properties that the class instance can add

• Private variables limit our call to properties

• __slots__ Binding Properties limits Our addition to attributes

Class Student (object):

__slots__ = (' name ', ' age ') # defines the name of the property allowed to bind with a tuple

Note :

• __slots__ the defined properties only work on the current class instance , it has no effect on inherited subclasses.

• If __slots__ is also defined in a subclass, A subclass instance allows a defined property to be its own __slots__ plus the parent class's __slots__

Python Learning note __7.1 using __slots__