Python multi-inheritance, python inheritance

Python multi-inheritance, python inheritance

Yesterday, my roommate dragged me to eat chicken, so I didn't learn it. I should reflect on it. I only want to learn a little more today, so I will make up for the previous day.

Today I learned more about python inheritance.

I think it is still a little difficult to inherit more. Today I am studying the real-income method of multi-inheritance. I accidentally wrote the name of the constructor of the parent class wrong, And then I encountered a bug. I have been searching for it for a long time, I found that the error was written above, and the error reported by the result editor is far from the one I actually encountered. Therefore, you need to write the code carefully and it is really annoying to find a bug.

Now let's get down to the truth and start the text.

 

 

Class People (object): # This is the first parent class.
Name = ""
Age = 0
_ Weight = 0 # private attribute

Def _ init _ (self, name, age, weight ):
Self. name = name
Self. age = age
Self. _ weight = weight

Def speak (self ):
Print (self. name, self. age, self. _ weight)


# When inheriting a class, the class name is enclosed in brackets and you need to inherit the class. It can be seen that this is a single inheritance.
Class Student (People): # A subclass is defined here and inherits the people class above.
Grade = ""
Def _ init _ (self, name, age, weight, grade ):
People. _ init _ (self, name, age, weight)
Self. grade = grade

Def print_sudent (self ):
Print (self. grade)

# Create another class here

Class Speaker (object ):
Topic = ""
Name = ""
Def _ init _ (self, name, topic ):
Self. name = name
Self. topic = topic

Def print_speak (self ):
Print (self. name, self. topic)

# Here is the main character of today. We can see that the name of the parent class you need to inherit is in the brackets after the class name.
# Note: the sequence of the parent class is very important. For example, you need to call a method that does not exist in the parent class, the python interpreter looks for the method you call from left to right in the parent class.

Class Sample (Student, Speaker ):
A = ""
# This is very important. Here is the method of inheriting the constructor of the parent class.
Def _ init _ (self, name, age, weight, grade, topic, ):
Student. _ init _ (self, name, age, weight, grade)
Speaker. _ init _ (self, name, topic)
Self. a =

# Method Rewriting: if the parent class has this method, but the function cannot meet the requirements of the subclass, then you can define a new function with the same name as the parent class in the subclass,
# When this instance calls this method, it will call the method you override in the subclass.
Def print_speak (self ):
Print (self. name, self. age, self. grade, self. topic, self.)

# Use subclass to generate instances

Test = Sample ("tim", 25, 80, 99, "python", 10)

# Call the method to override a subclass
Test. print_speak ()