首页 > 代码库 > Python2.7 学习体会 @classmethod @staticmethod @property 之间的关系
Python2.7 学习体会 @classmethod @staticmethod @property 之间的关系
先来一个实例场景,然后测试,比较,不懂的话到网上找资料:
#!/usr/bin/env python
#!/usr/bin/env python
class Date(object):
def __init__(self,year=0,month=0,day=0):
self.year = year
self.month = month
self.day = day
@staticmethod
def statictime(self):
return "{year}-{month}-{day}".format(
year = self.year,
month = self.month,
day = self.day
)
@property
def time(self):
return "{year}-{month}-{day}".format(
year = self.year,
month = self.month,
day = self.day
)
@classmethod
def from_string(cls,string):
year,month,day = map(str,string.split(‘-‘))
date = cls(year,month,day)
return date
def showtime(self):
return "{M}/{D}/{Y}".format(
Y = self.year,
M = self.month,
D = self.day
)
print ‘-‘*20
date = Date("2016","11","09")
print ‘date @property ‘,date.time
print ‘date @normal ‘,date.showtime()
print ‘date @staticmethod ‘,date.statictime(date)
print ‘-‘*20
date_string = ‘2017-05-27‘
year,month,day = map(str,date_string.split(‘-‘))
date2 = Date(year,month,day)
print ‘date2 @property ‘,date2.time
print ‘date2 @noraml ‘,date2.showtime()
print ‘date2 @staticmethod ‘,date2.statictime(date2)
print ‘-‘*20
date3 = Date.from_string(date_string)
print ‘date3 @property ‘,date3.time
print ‘date3 @normal ‘,date3.showtime()
print ‘date3 @staticmethod ‘,date3.statictime(date3)
运行结果:
--------------------
date @property 2016-11-09
date @normal 11/09/2016
date @staticmethod 2016-11-09
--------------------
date2 @property 2017-05-27
date2 @noraml 05/27/2017
date2 @staticmethod 2017-05-27
--------------------
date3 @property 2017-05-27
date3 @normal 05/27/2017
date3 @staticmethod 2017-05-27
初步测试结果:
1、@property 装饰器后面的函数,在实例调用中不能加(),不然会出现错误:TypeError: ‘str‘ object is not callable
2、正常的方法,在实例调用中如果不加() ,就是不运行函数,而只是返回函数(方法)的地址:
3、@staticmethod 装饰器后面的函数,在实例调用中必须加对像参数,不然会提示:TypeError: statictime() takes exactly 1 argument (0 given)
4、@classmethod 我的初步理解:是对类,进行重新的定义初始化。
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实例原型链接:http://mp.weixin.qq.com/s/6NJAoFI-DbsNQdA3M1SIMw (非常推荐大家去看看)
明天继续….
Python2.7 学习体会 @classmethod @staticmethod @property 之间的关系