66 lines
1.3 KiB
Python
66 lines
1.3 KiB
Python
|
"""
|
||
|
|
|
||
|
|
属性的使用
|
||
|
|
- 访问器/修改器/删除器
|
||
|
|
- 使用__slots__对属性加以限制
|
||
|
|
|
||
|
|
Version: 0.1
|
||
|
|
Author: 骆昊
|
||
|
|
Date: 2018-03-12
|
||
|
|
|
||
|
|
"""
|
||
|
|
|
||
|
|
|
||
|
|
class Car(object):
|
||
|
|
|
||
|
|
__slots__ = ('_brand', '_max_speed')
|
||
|
|
|
||
|
|
def __init__(self, brand, max_speed):
|
||
|
|
self._brand = brand
|
||
|
|
self._max_speed = max_speed
|
||
|
|
|
||
|
|
@property
|
||
|
|
def brand(self):
|
||
|
|
return self._brand
|
||
|
|
|
||
|
|
@brand.setter
|
||
|
|
def brand(self, brand):
|
||
|
|
self._brand = brand
|
||
|
|
|
||
|
|
@brand.deleter
|
||
|
|
def brand(self):
|
||
|
|
del self._brand
|
||
|
|
|
||
|
|
@property
|
||
|
|
def max_speed(self):
|
||
|
|
return self._max_speed
|
||
|
|
|
||
|
|
@max_speed.setter
|
||
|
|
def max_speed(self, max_speed):
|
||
|
|
if max_speed < 0:
|
||
|
|
raise ValueError('Invalid max speed for car')
|
||
|
|
self._max_speed = max_speed
|
||
|
|
|
||
|
|
def __str__(self):
|
||
|
|
return 'Car: [品牌=%s, 最高时速=%d]' % (self._brand, self._max_speed)
|
||
|
|
|
||
|
|
|
||
|
|
car = Car('QQ', 120)
|
||
|
|
print(car)
|
||
|
|
# ValueError
|
||
|
|
# car.max_speed = -100
|
||
|
|
car.max_speed = 320
|
||
|
|
car.brand = "Benz"
|
||
|
|
# 使用__slots__属性限制后下面的代码将产生异常
|
||
|
|
# car.current_speed = 80
|
||
|
|
print(car)
|
||
|
|
# 如果提供了删除器可以执行下面的代码
|
||
|
|
# del car.brand
|
||
|
|
# 属性的实现
|
||
|
|
print(Car.brand)
|
||
|
|
print(Car.brand.fget)
|
||
|
|
print(Car.brand.fset)
|
||
|
|
print(Car.brand.fdel)
|
||
|
|
# 通过上面的代码帮助学生理解之前提到的包装器的概念
|
||
|
|
# Python中有很多类似的语法糖后面还会出现这样的东西
|