Python object-Oriented programming basics

Object-oriented Keywords: class, object, instance, method

Object-oriented three main features: encapsulation, inheritance, polymorphism

Class Foo:      # defines the name    def F1 (self):     # F1 method        Print ("success") obj = Foo ()    # Create Object Obj.f1 ()          # by Object execution method

Class and object relationships:

The self parameter is a python parameter that automatically passes the value, and the object executes the method.

Class Sqlhelp ():    def __init__ (self, a1, A2, A3):         # This method automatically executes the method that the object executes, and that is the        print ("Auto-execute init")        self.host = A1        self.name = a2        self.pwd = A3    def find (self):        passobj1 = sqlhelp (' c1.salt.com ', ' DJC ', ' 100 ')    # parameters correspond to A1,a2,a3print (obj1.host) respectively

>>>
Automatic execution
C1.salt.com

　　

Encapsulates objects in an object

Class C1:    def __init__ (self, Name, obj):        self.name = name        self.obj = objclass C2:    def __init__ (self, Name, age):        self.name = name        Self.age = Age    def show (self):        print ("Mdzz") class C3:    def __init __ (self, A1):        self.aaa = a1c2_obj = C2 ("DJC", 19) # to write before C1 class C1_obj = C1 ("SB", c2_obj) ret = C1_obj.obj.nameprint (re T) >>>djcc3_obj = C3 (c1_obj) Ret2 = C3_obj.aaa.obj.show () print (Ret2) >>>mdzz

　　

Simple single Inheritance

# inheritance is equivalent to copying a method of the parent class to a subclass, rather than going to the parent class to take

Class F1:         # parent class, base class    def show (self):        print ("F1")    def foo (self):        print (Self.name) class F2 (F1):          # subclass, Derived class     def __init__ (self, name)        self.name = Nameobj = F2 ("DJC") Obj.foo () >>>DJC

　　

Complex single inheritance

Class F1:    def F1 (self): self        . F2 ()                # performs F2 's F2    def F2 (self):        print ("F1,f2") class F2 (F1):    def-F3 (self): self                 . F1 ()                 # performs F1 's F1    def F2 (self):        print ("f2,f2") obj = F2 () obj. F3 ()      # own method first, as a subclass do not ignore the inherited method of the parent class, if you do not have to go to the parent class to find >>>F2,F2

Simple Multiple inheritance

Class C1:    def f2 (self):        print ("C1") Class C2:    def f2 (self):        print ("C2") class C3 (C2,C1):         # Left Priority    def f3 (self):        Passobj = C3 () obj.f2 () >>>c2

Slightly more complex multiple inheritance

Class C0:    def f2 (self):        print ("C0") class C1:    def f2 (self):        print ("C1") Class C2 (C0):    def F1 ( Self):        print ("C2") class C3 (C2,c1):    def f3 (self):        Passobj = C3 () obj.f2 () >>>c0

　　

Complex multiple inheritance

Class c_2:    def f2 (self):        print ("c_2") class C_1 (c_2):    def f2 (self):        print ("C_1") class C0 (c_2):    def F1 (self):        print ("C0") class C1 (c_1):    def F1 (self):        print ("C1") Class C2 (C0):    def F1 (self):        Print ("C2") class C3 (C2,c1):    def f3 (self):        Passobj = C3 () obj.f2 () >>>c-1

Class h5:    def Forever (self):        Self.run () class H4 (H5):    def __init__ (self):        pass    def run (self ):        self.process ()    def process (self):        print ("H4") class H3 (H4):    def-__init__ (self):        Passclass H2:    def process (self):        print ("H2") class A (H2, H3):    passobj = A () obj.forever () >>>h2

　

Python object-oriented programming basics