Python笔记6#面向对象高级编程一

#定义一个类Student
>>> class Student(object):
...     pass
...
#创建类Student的一个实例stu1
>>> stu1 = Student()
#给实例绑定一个属性name
>>> stu1.name = ‘michael‘
>>> stu1.name
michael
#给实例绑定一个属性age
>>> stu1.age = ‘25‘
>>> stu1.age
25
#定义set_age()函数作为实例方法
>>> def set_age(self, age):
...     self.age = age
...
#导入MethodType模块
>>> from types import MethodType
#给实例stu1绑定方法set_age()
>>> stu1.set_age = MethodType(set_age, stu1)
#调用实例方法
>>> stu1.set_age(20)
#测试结果
>>> stu1.age
20
#创建类Student的另一个实例stu2
>>> stu2 = Student()
#测试给stu1绑定的属性name和方法set_age()是否可用于stu2
>>> stu2.name
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: ‘Student‘ object has no attribute ‘name‘
>>> stu2.set_age(22)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: ‘Student‘ object has no attribute ‘set_age‘
#创建一个类方法，并绑定给类Student
>>> def set_score(self, score):
...     self.score = score
...
>>> Student.set_score = MethodType(set_score, Student)
#测试绑定类Student的方法set_score()是否可用于stu1和stu2
>>> stu1.set_score(98)
>>> stu1.score
98
>>> stu2.set_score(70)
>>> stu2.score
70

>>> class Student(object):
#用tuple定义允许绑定的属性名称
...     __slots__ = (‘name‘, ‘age‘)
...
>>> stu3 = Student()
>>> stu3.name = ‘jack‘
>>> stu3.age = ‘22‘
#测试未绑定的属性score能否添加
>>> stu3.score = ‘86‘
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: ‘Student‘ object has no attribute ‘score‘
#测试__slots__对子类是否起作用
>>> class Firstgrade(Student):
...     pass
...
>>> stu4 = Firstgrade()
>>> stu4.name = ‘david‘
>>> stu4.age = ‘12‘
>>> stu4.score = ‘90‘

class Student(object):
    def __init__(self):
        self._score = None
    
#为属性score增加getter
    @property
    def score(self):
        print(‘you get the score!‘)
        return self._score
    
#为属性score增加setter
    @score.setter
    def score(self, value):
        print(‘you set the score!‘)
        self._score = value
    
#为属性score增加deleter
    @score.deleter
    def score(self):
        print(‘you delete the score!‘)
        del self._score


stu1 = Student()
print(‘-‘ * 50)
stu1.score = 88
print(‘-‘ * 50)
print(stu1.score)
print(‘-‘ * 50)
stu1.score = 92
print(stu1.score)
del stu1.score

--------------------------------------------------
you set the score!
--------------------------------------------------
you get the score!
88
--------------------------------------------------
you set the score!
you get the score!
92
you delete the score!

class Animal(object):
    pass

class Flyable(object):
    def fly(self):
        print(‘flying...‘)

#定义一个多重继承的子类
class Eagle(Animal, Flyable):
    pass