Python Class (iv)-reflection

Reflection is the State, property, method by which the program runs through a string mapping or modification

There are 4 ways of doing this:

Hasattr ():

Hasattr (object,string): Object instantiated As String

A method or property that determines whether the object has a string in it, returns a Boolean type

#-*-Coding:utf-8-*-__author__ = "MuT6 Sch01ar" class Person (object):    def __init__ (self,name):        self.name = name    def Eat (self):        print ('%s are eating '%self.name) if __name__ = = ' __main__ ':    p = person (' John ') #实例化Person类 
   argu = input (">>>:"). Strip ()    print (Hasattr (P,ARGU))

Run, enter name

Class has the name attribute, which returns true

Input Eat

Class has eat This method, returns True

Enter test

The class does not have the test property and method, which returns false

GetAttr ():

GetAttr (Object,string[,default]): Object is instantiated, string is the default value

Gets the method or property of the object, based on string strings, that returns the value of default if the object does not have a string property or method in it, and if the value of default is not set, an error will be

Gets the method in the class and calls the

#-*-Coding:utf-8-*-__author__ = "MuT6 Sch01ar" class Person (object):    def __init__ (self,name):        self.name = name    def Eat (Self,food):        print ('%s is eating%s '% (Self.name,food)) if __name__ = = ' __main__ ':    p = person (' John ')    Argu = input (">>>:"). Strip ()    if Hasattr (P,ARGU):        getattr (P,argu) (' Meat ')

Execution results

Get the value of a property in a class

#-*-Coding:utf-8-*-__author__ = "MuT6 Sch01ar" class Person (object):    def __init__ (self,name):        self.name = name    def Eat (Self,food):        print ('%s is eating%s '% (Self.name,food)) if __name__ = = ' __main__ ':    p = person (' John ')    Argu = input (">>>:"). Strip ()    print (GetAttr (P,ARGU))

If the string is not a property in the class, the specified default value is returned

#-*-Coding:utf-8-*-__author__ = "MuT6 Sch01ar" class Person (object):    def __init__ (self,name):        self.name = name    def Eat (Self,food):        print ('%s is eating%s '% (Self.name,food)) if __name__ = = ' __main__ ':    p = person (' John ')    Argu = input (">>>:"). Strip ()    print (GetAttr (P,argu, "test"))

Enter a, the class does not have a property, then return the default value of the specified test

SetAttr ():

SetAttr (Object,string,value): Object is instantiated, string is string, value is

SetAttr () to set a method or property

A function that sets the passed string as string to the value name, and then invokes the GetAttr ()

#-*-Coding:utf-8-*-__author__ = "MuT6 Sch01ar" class Person (object):    def __init__ (self,name):        self.name = name    def Eat (Self,food):        print ('%s is eating%s '% (Self.name,food)) #在类外定义一个函数def Talk:    print ("%s is Talking "%self.name) if __name__ = = ' __main__ ':    p = person (' John ')    Argu = input (" >>>: "). Strip ()    SetAttr (p,argu,talk) #把传入的字符串设置为talk函数    getattr (P,argu) (p) #把实例化的对象传入函数中

Run, enter a

Instead of calling the talk () function, the string A that is set to the talk () function

SetAttr () Setting properties

#-*-Coding:utf-8-*-__author__ = "MuT6 Sch01ar" class Person (object):    def __init__ (self,name):        self.name = name    def Eat (Self,food):        print ('%s is eating%s '% (Self.name,food)) if __name__ = = ' __main__ ':    p = person (' John ')    Argu = input (">>>:"). Strip ()    setattr (P,argu, ' man ') #设置属性    print (GetAttr (P,ARGU))

The string passed in, if not a property in the class, creates a new property string for the class and assigns value to the new property

The string passed in, and if it is a property in the class, value overrides the original property

Delattr ():

Delattr (object,string): Remove string Property from Object

#-*-Coding:utf-8-*-__author__ = "MuT6 Sch01ar" class Person (object):    def __init__ (self,name):        self.name = name    def Eat (Self,food):        print ('%s is eating%s '% (Self.name,food)) if __name__ = = ' __main__ ':    p = person (' John ')    Argu = input (">>>:"). Strip ()    delattr (P,argu)    print (GetAttr (P,ARGU))

Run, enter name

Error, the name attribute is not in the person class

Python Class (iv)-reflection