An object-oriented:
Object-oriented programming is an idea, is a way for programmers to better programming ideas.
The core is the object, the program is a set of objects, is responsible for scheduling control these objects to interact with the task.
In the object-oriented programmer angle changed into a particular conductor from the operator.
He stressed: object is not created out of thin air, we need to design their own
Object-oriented three major advantages:
- Scalability
- flexibility
- Reuse (code can be used multiple times)
Disadvantages:
- Increased complexity of the program
- We can not accurately predict the results
Be used: high scalability requirements of the program, typically directly to the user. For example QQ, micro-letter
Second, process-oriented
The core concern is the process, step by step process is the execution step in doing both before doing
Process for the advantages:
Poor scalability, maintainability
scenes to be used:
Requirements for lower extension programs such as: system kernel, git, calculator
** not require any program object-oriented, have to analyze the specific needs
Third, the classes and objects
1. classes and objects
This is the core concepts oop (object-oriented programming) in
Categories: either type, class, an abstract concept, is a set of features and the same behavior with the same object
Object: a thing is the existence of specific, have their own characteristics and behavior of the object is a combination of characteristics and skills
The relationship between classes and objects
Class contains a series of objects, the object belongs to a class.
In life is to have only the object classes, and the program is the first class and then have the object, we have to tell the computer objects of this class has what features, what kind of behavior.
Summary: When using object-oriented programming, the first step is the need to think what kind of objects, objects have what kind of features and behavior, which summed up according to the type of information required.
2, create classes and objects
The syntax for defining classes
Class Name of the class:
Content class (described attributes and skills)
Description property with variable skill with function
Name of the class writing requirements:
The first is intended to see to know the name of the name is big hump nomenclature
Hump word is capitalized, the big hump is the first letter capitalized, small hump is the first letter lowercase
The syntax to create objects
Define a class
Class Person：
Pass
Then create an object:
P = Person()
Properties can be written in a class, class attributes are common to all objects
Properties can also be written in an object, object properties, each object is unique (not the same)
Note: If the same attribute is present in the class and object, sequential access this property is the first property in an object, if not found in the object, then go inside to find the class attribute
Increase property
The object variable name. Attribute name = attribute value
Delete property
Variable name del objects. Attribute name
modify
Object = new attribute value
View property access all attributes of an object
print (Object .__ dict__)
Class information access objects
print (Object .__ class__)
__init__ method
Initialization method is called, is essentially a function
Features 1: When the object is instantiated, the method is performed automatically __init__
Feature 2: automatically object as the first argument, the parameter name is self, self can be another name, but it is not recommended to change
Function: an initial value of the user is attached to the object, the function can not have any return value, so only a predetermined None
Exercise: Create a class with several properties to set the property to him by the initialization method
class Dog:
def __init__(self,kind,color,age):
self.kind = kind
self.color = color
self.age = age
d1 = Dog ( "two ha", "black and white", 1)
d1 = Dog ( "Teddy", "brown", 2)
The essence of the object function is to integrate data and process the data together, so to get an object on both his function data and processing data to be processed
- Bound method object
Class methods are bound method objects by default
It is special because:
- When the function is called an object, the object itself automatically passed as the first argument
- When the class name to call, it is a normal function, there are several parameters to pass several parameters
Exercise: Write a class of students, with a greeting skills to be able to export its own name information
class Student:
def __init__(self,name):
self.name = name
def say_hi(self):
print("hello my name is %s" % self.name)
st = Student(“lila”)
st.say_hi()
4. The method of binding the class
Class binding method used to decorate @classmethod
Special features: Regardless of class or object calls are automatically incoming class itself, as the first argument
** when binding to the object: When the function logic requires access to data objects in time
** When binding to the class: When the data logic functions to be accessed when the class
The non-binding method
Or static method is called, is that is does not need to access the data class, you do not need data access objects
Syntax: @staticmethod
Def function name ():
'Function body