详解Python3 中hasattr()、getattr()、setattr()、delattr()函数及示例代码

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：

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.__init__ at 0x1006d5620>, 'people_info': <function People.people_info at 0x10205d1e0>, '__dict__': <attribute '__dict__' of 'People' objects>, '__weakref__': <attribute '__weakref__' of 'People' objects>, '__doc__': None}

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：

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

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：

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.__init__ at 0x1007d5620>, 'people_info': <function People.people_info at 0x10215d1e0>, '__dict__': <attribute '__dict__' of 'People' objects>, '__weakref__': <attribute '__weakref__' of 'People' objects>, '__doc__': None, 'x': 111}

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：