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@classmethod, @staticmethod和@property这三个装饰器的使用对象是在类中定义的函数。下面的例子展示了它们的用法和行为:

时间:2017-04-24 12:38:39      阅读:269      评论:0      收藏:0      [点我收藏+]

标签:错误   not   sel   obj   instance   attr   getter   callable   setter   

class MyClass(object):
    def __init__(self):
        self._some_property = "properties are nice"
        self._some_other_property = "VERY nice"
    def normal_method(*args,**kwargs):
        print "calling normal_method({0},{1})".format(args,kwargs)
    @classmethod
    def class_method(*args,**kwargs):
        print "calling class_method({0},{1})".format(args,kwargs)
    @staticmethod
    def static_method(*args,**kwargs):
        print "calling static_method({0},{1})".format(args,kwargs)
    @property
    def some_property(self,*args,**kwargs):
        print "calling some_property getter({0},{1},{2})".format(self,args,kwargs)
        return self._some_property
    @some_property.setter
    def some_property(self,*args,**kwargs):
        print "calling some_property setter({0},{1},{2})".format(self,args,kwargs)
        self._some_property = args[0]
    @property
    def some_other_property(self,*args,**kwargs):
        print "calling some_other_property getter({0},{1},{2})".format(self,args,kwargs)
        return self._some_other_property
o = MyClass()
# 未装饰的方法还是正常的行为方式,需要当前的类实例(self)作为第一个参数。
o.normal_method 
# <bound method MyClass.normal_method of <__main__.MyClass instance at 0x7fdd2537ea28>>
o.normal_method() 
# normal_method((<__main__.MyClass instance at 0x7fdd2537ea28>,),{})
o.normal_method(1,2,x=3,y=4) 
# normal_method((<__main__.MyClass instance at 0x7fdd2537ea28>, 1, 2),{‘y‘: 4, ‘x‘: 3})
# 类方法的第一个参数永远是该类
o.class_method
# <bound method classobj.class_method of <class __main__.MyClass at 0x7fdd2536a390>>
o.class_method()
# class_method((<class __main__.MyClass at 0x7fdd2536a390>,),{})
o.class_method(1,2,x=3,y=4)
# class_method((<class __main__.MyClass at 0x7fdd2536a390>, 1, 2),{‘y‘: 4, ‘x‘: 3})
# 静态方法(static method)中除了你调用时传入的参数以外,没有其他的参数。
o.static_method
# <function static_method at 0x7fdd25375848>
o.static_method()
# static_method((),{})
o.static_method(1,2,x=3,y=4)
# static_method((1, 2),{‘y‘: 4, ‘x‘: 3})
# @property是实现getter和setter方法的一种方式。直接调用它们是错误的。
# “只读”属性可以通过只定义getter方法,不定义setter方法实现。
o.some_property
# 调用some_property的getter(<__main__.MyClass instance at 0x7fb2b70877e8>,(),{})
# ‘properties are nice‘
# “属性”是很好的功能
o.some_property()
# calling some_property getter(<__main__.MyClass instance at 0x7fb2b70877e8>,(),{})
# Traceback (most recent call last):
#   File "<stdin>", line 1, in <module>
# TypeError: ‘str‘ object is not callable
o.some_other_property
# calling some_other_property getter(<__main__.MyClass instance at 0x7fb2b70877e8>,(),{})
# ‘VERY nice‘
# o.some_other_property()
# calling some_other_property getter(<__main__.MyClass instance at 0x7fb2b70877e8>,(),{})
# Traceback (most recent call last):
#   File "<stdin>", line 1, in <module>
# TypeError: ‘str‘ object is not callable
o.some_property = "pythontab"
# calling some_property setter(<__main__.MyClass object at 0x7fb2b7077890>,(‘pythontab‘,),{})
o.some_property
# calling some_property getter(<__main__.MyClass object at 0x7fb2b7077890>,(),{})
# ‘pythontab‘
o.some_other_property = "pythontab.com"
# Traceback (most recent call last):
#   File "<stdin>", line 1, in <module>
# AttributeError: can‘t set attribute
o.some_other_property
# calling some_other_property getter(<__main__.MyClass object at 0x7fb2b7077890>,(),{})

 

@classmethod, @staticmethod和@property这三个装饰器的使用对象是在类中定义的函数。下面的例子展示了它们的用法和行为:

标签:错误   not   sel   obj   instance   attr   getter   callable   setter   

原文地址:http://www.cnblogs.com/howhy/p/6755679.html

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