hasattr(object,name):判断object对象里是否有name属性或者方法,有=>True,否=>False!    

>>> class test():...     name="xiaohua"...     def run(self):...             return "HelloWord"...>>> t=test()>>> hasattr(t, "name") #判断对象有name属性True>>> hasattr(t, "run")  #判断对象有run方法True>>>

getattr(object,name[,default]):获取object对象里的name属性或者方法,属性存在=>打印,不存在=>默认值(默认值可选),如果是对象里的方法,返回的是方法的内存地址,加()就可运行!

>>> class test():...     name="xiaohua"...     def run(self):...             return "HelloWord"...>>> t=test()>>> getattr(t, "name") #获取name属性，存在就打印出来。'xiaohua'>>> getattr(t, "run")  #获取run方法，存在就打印出方法的内存地址。
     
      >>>> getattr(t, "run")()  #获取run方法，后面加括号可以将这个方法运行。'HelloWord'>>> getattr(t, "age")  #获取一个不存在的属性。Traceback (most recent call last):  File "
      
       ", line 1, in 
       
        AttributeError: test instance has no attribute 'age'>>> getattr(t, "age","18")  #若属性不存在，返回一个默认值。'18'>>>
       
      
     

setattr(object,name,values):给对象的属性赋值,若属性不存在,则先创建再赋值!

>>> class test():...     name="xiaohua"...     def run(self):...             return "HelloWord"...>>> t=test()>>> hasattr(t, "age")   #判断属性是否存在False>>> setattr(t, "age", "18")   #为属相赋值，并没有返回值>>> hasattr(t, "age")    #属性存在了True>>>

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一种综合的用法是：判断一个对象的属性是否存在，若不存在就添加该属性。

 

>>> class test():...     name="xiaohua"...     def run(self):...             return "HelloWord"...>>> t=test()>>> getattr(t, "age")    #age属性不存在Traceback (most recent call last):  File "
     
      ", line 1, in 
      
       AttributeError: test instance has no attribute 'age'>>> getattr(t, "age", setattr(t, "age", "18")) #age属性不存在时，设置该属性'18'>>> getattr(t, "age")  #可检测设置成功'18'>>>