""" """
__author__ = 'shaozhiqi'
# 绑定属性时，如果我们直接把属性暴露出去，虽然写起来很简单，
# 但是，没办法检查参数，导致可以把参数随便改
# 比如想限制student score的范围
class Student(object):
def get_score(self):
return self._score
def set_score(self, value):
if not isinstance(value, int):
raise ValueError('score must be an integer!')
if value < 0 or value > 100:
raise ValueError('score must between 0 ~ 100!')
self._score = value
s = Student()
s.set_score(60)
print(s.get_score()) # 60
# print(s.set_score(1000)) # ValueError: score must between 0 ~ 100!
# ---------------------property-------------------------------------
# 上述方法不太简洁,使用property 修改
# @property装饰器就是负责把一个方法变成属性调用,默认是只读
class Student1(object):
@property
def score(self):
return self._score
@score.setter
def score(self, value):
if not isinstance(value, int):
raise ValueError('score must be an integer!')
if value < 0 or value > 100:
raise ValueError('score must between 0 ~ 100!')
self._score = value
s1 = Student1()
s1.score = 60
# s1.score = 9999999 # ValueError: score must between 0 ~ 100!
# 报错说明里面有set 方法的实现，如果直接暴露的属性，就不会报错
# 只读属性-------------------------------------------------------
class Student(object):
@property
def birth(self):
return self._birth
@birth.setter
def birth(self, value):
self._birth = value
@property
def age(self):
return 2019 - self._birth
# birth 是一个可读写属性，而age是一个只读属性
# age的值可以根据birth计算
s = Student()
s.birth = 1990
print(s.birth) # 注意如果不赋值直接读 会error
# s.age=100 # error AttributeError: can't set attribute property 默认是只读
print(s.age) # 29
