The role of reflection in a Python class

#Coding:utf-8" "#反射的基本用法: Hasattr Determines whether a method exists in the instance getattr specifies a method name, gets the memory address of the method, adds "()" parentheses and executes" "ImportSYSclassWebServer (object):def __init__(self,host,port): Self.host=host Self.port=PortdefStart (self):Print("Server is starting ...")    defStop (self):Print("Server is stopping")    defRestart (self): Self.stop () Self.start ()#Example: Get the first content of a user input, call the appropriate methodif __name__=="__main__":    #sys.argv[1] means: Receives the first parameter entered by the user    #method One: This method can be implemented, but very low (), do not recommend the use of    #Server = WebServer ("127.0.0.1", 3306)    #cmd_server = {"Start": Server.start, "Stop": server.stop, "restart": Server.restart}    #if sys.argv[1] in Cmd_server:    #Cmd_server[sys.argv[1]] ()    ##方法二: But this method has a problem, how to call the user input string name corresponding method?     #cmd_server = sys.argv[1]    #if cmd_server in webserver.__dict__:    #print (cmd_server)    #WebServer ("127.0.0.1", 3306). Cmd_server #cmd_server为用户输入的字符串名字, but that's obviously not a good call.    #method Three: Use the Hasattr and GetAttr methods to determine if the method exists in the object and get the memory address of the method in the objectServer = WebServer ("127.0.0.1", 3306)    ifHasattr (Server,sys.argv[1]):#hasattr: Determines whether a class contains a method or propertyFunc = GetAttr (server,sys.argv[1])#getattr; get Server.start memory addressfunc ()

" "SetAttr binds a function to an instance description: How do you bind a function outside a class to an instance? " "ImportSYSclassWebServer (object):def __init__(self,host,port): Self.host=host Self.port=PortdefStart (self):Print("Server is starting ...")    defStop (self):Print("Server is stopping")    defRestart (self): Self.stop () Self.start ()#How do I bind this function to an instance? defRun_server (obj,name):Print("runing is%s"%Obj.restart (), name)if __name__=="__main__": Server= WebServer ("localhost", 3306) setattr (server,'Run', Run_server)#The Test_run function is bound to the server instance by the SetAttr method, which is called "Run" .Server.run (Server,"Apache")

" "Delattr Delete An instance or a method in a class" "ImportSYSclassWebServer (object):def __init__(self,host,port): Self.host=host Self.port=PortdefStart (self):Print("Server is starting ...")    defStop (self):Print("Server is stopping")    defRestart (self): Self.stop () Self.start ()defrun_server (name):Print("runing is%s", name)if __name__=="__main__": Server= WebServer ("localhost", 3306) setattr (server,'Run', Run_server) delattr (WebServer,"Start")#Delete a method inside a classDelattr (Server,"Host")#Delete An instance's propertiesDelattr (Server,'Run')#Remove properties added to an instance via SetAttr    Print(server.__dict__, WebServer.__dict__)#View

The role of reflection in a Python class