Python3 中hasattr()、getattr()、setattr()、delattr()函数及示例代码
本文通过示例代码给大家详细介绍了python3 中hasattr()、getattr()、setattr()、delattr()函数,非常不错,具有参考借鉴价值,需要的朋友参考下吧
hasattr()函数
hasattr()函数用于判断是否包含对应的属性
语法:
hasattr(object,name)
参数:
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object--对象
name--字符串,属性名
返回值:
如果对象有该属性返回True,否则返回False
示例:
class People: country='China' def __init__(self,name): self.name=name def people_info(self): print('%s is xxx' %(self.name))obj=People('aaa')print(hasattr(People,'country'))#返回值:Trueprint('country' in People.__dict__)#返回值:Trueprint(hasattr(obj,'people_info'))#返回值:Trueprint(People.__dict__)##{'__module__': '__main__', 'country': 'China', '__init__': <function>, 'people_info': <function>, '__dict__': <attribute>, '__weakref__': <attribute>, '__doc__': None}</attribute></attribute></function></function>
getattr()函数
描述:
getattr()函数用于返回一个对象属性值
语法:
getattr(object,name,default)
参数:
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object--对象
name--字符串,对象属性
default--默认返回值,如果不提供该参数,在没有对于属性时,将触发AttributeError。
返回值:
返回对象属性值
class People: country='China' def __init__(self,name): self.name=name def people_info(self): print('%s is xxx' %(self.name))obj=getattr(People,'country')print(obj)#返回值China#obj=getattr(People,'countryaaaaaa')#print(obj)#报错# File "/getattr()函数.py", line 32, in <module># obj=getattr(People,'countryaaaaaa')# AttributeError: type object 'People' has no attribute 'countryaaaaaa'obj=getattr(People,'countryaaaaaa',None)print(obj)#返回值None</module>
setattr()函数
描述:
setattr函数,用于设置属性值,该属性必须存在
语法:
setattr(object,name,value)
参数:
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object--对象
name--字符串,对象属性
value--属性值
返回值:
无
class People: country='China' def __init__(self,name): self.name=name def people_info(self): print('%s is xxx' %(self.name))obj=People('aaa')setattr(People,'x',111) #等同于People.x=111print(People.x)#obj.age=18setattr(obj,'age',18)print(obj.__dict__)#{'name': 'aaa', 'age': 18}print(People.__dict__)#{'__module__': '__main__', 'country': 'China', '__init__': <function>, 'people_info': <function>, '__dict__': <attribute>, '__weakref__': <attribute>, '__doc__': None, 'x': 111}</attribute></attribute></function></function>
delattr()函数
描述:
delattr函数用于删除属性
delattr(x,'foobar)相当于del x.foobar
语法:
setattr(object,name)
参数:
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object--对象
name--必须是对象的属性
返回值:
无
示例:
class People: country='China' def __init__(self,name): self.name=name def people_info(self): print('%s is xxx' %(self.name))delattr(People,'country') #等同于del People.countryprint(People.__dict__){'__module__': '__main__', '__init__': <function>, 'people_info': <function>, '__dict__': <attribute>, '__weakref__': <attribute>, '__doc__': None}</attribute></attribute></function></function>
补充示例:
class Foo: def run(self): while True: cmd=input('cmd>>: ').strip() if hasattr(self,cmd): func=getattr(self,cmd) func() def download(self): print('download....') def upload(self): print('upload...')# obj=Foo()# obj.run()