day 23
1.isinstance/issubclass
class Bar: pass class Foo(Bar): pass print(issubclass(Foo,Bar)) obj=Foo() print(isinstance(obj,Foo)) # print(isinstance([1,2,3],list)) # print(type(obj) is Foo) # print(type([1,2,3]) is list)
2.反射:通过字符串来反射/映射到对象/类的属性上
class People: def __init__(self,name1,age): self.name2=name1 self.age=age def run(self): print('%s is running' %self.name2) obj=People('egon',18) print(hasattr(obj,'name2')) # 'name' in obj.__dict__ # print(getattr(obj,'name')) # obj.__dict__['name'] # print(getattr(obj,'xxx',None)) # obj.__dict__['xxx'] # setattr(obj,'name','EGON') #obj.__dict__['name']='EGON' # setattr(obj,'xxx',1111) #obj.__dict__['xxx']=111 # print(obj.name) # print(obj.__dict__) # delattr(obj,'name') # print(obj.__dict__) # import os # os.remove # print(hasattr(os,'remove')) # # class Ftp: # def get(self): # print('get') # # def put(self): # print('put') # # def login(self): # print('login') # # def run(self): # while True: # cmd=input('>>>: ').strip() #cmd='get' # if hasattr(self,cmd): # method=getattr(self,cmd) # method() # else: # print('输入的方法不存在') # # # obj=Ftp() # obj.run()
# __str__: 在对象被打印时自动触发,可以用来定义对象被打印时的输出信息 # 注意:必须返回一个字符串类型的值, # class People: # def __init__(self, name, age): # self.name = name # self.age = age # # def __str__(self): # # print('run..........') # return '<name:%s age:%s>' % (self.name, self.age) # obj1 = People('egon', 18) # print(obj1) # print(obj1.__str__()) # obj2=list([1,2,3]) # print(obj2) # __del__: 在对象被删除时先自动触发该方法,可以用来回收对象以外其他相关资源,比如系统资源 # class Foo: # def __init__(self,x,filepath,encoding='utf-8'): # self.x=x # self.f=open(filepath,'rt',encoding=encoding) # # def __del__(self): # print('run.....') # # 回收对象关联的其他资源 # self.f.close() # # obj=Foo(1,'a.txt') # # del obj # print('主===========>') # __call__: 在对象被调用时会自动触发该方法,可以用来??? class Foo: def __init__(self,x,y): self.x=x self.y=y def __call__(self, *args, **kwargs): print(self,args,kwargs) obj=Foo(1,2) obj(1,2,a=3,b=4) #obj.__call__(obj,1,2,a=3,b=4)