Python learning diary-Object-Oriented Programming (1), python Object-Oriented Programming

Python learning diary-Object-Oriented Programming (1), python Object-Oriented Programming

Python class and instance)

Assume that a shoe has two attributes: size and color.

Class can play a role in the template. Therefore, when creating an instance, you can forcibly enter some attributes that we think must be bound. By defining a special__init__When creating an instance, bind the size and color attributes to shoe. For example:

1 class Shoe(object):2 3     def __int__(self, size, color):4         self.size = size5         self.color = color

(Object) indicates the class to inherit from. If there is no suitable inheritance class, the object is used;

Self indicates the instance itself. Therefore, you can use the _ int _ method to add attributes to self;

 

Data encapsulation

Define the function for accessing data from the class so that data can be encapsulated. For example:

1 class Shoe(object):2 3     def __init__(self, size, color):4         self.size = size5         self.color = color6 7     def get_color(self):8         print('%s: %s' % (self.size, self.color))

To define a method, except that the first parameter isselfAnd other functions.

To call a method, you only need to call it directly on the instance variable,selfNo need to pass. Other parameters are passed in normally:

>>> bart.get_color()32: black

Another advantage of encapsulation is thatStudentClass to add new methods, suchget_grade:

 1 class Shoe(object): 2     ... 3  4     def get_level(self): 5         if self.size >= 40: 6             return 'A' 7         elif self.size >= 32: 8             return 'B' 9         else:10             return 'C'

You can simply call get_level, for example:

>>>46.get_level()'A'

NOTE: Refer to teacher Liao Xuefeng's website http://www.liaoxuefeng.com/wiki/0014316089557264a6b348958f449949df42a6d3a2e542c000/001431864715651c99511036d884cf1b399e65ae0d27f7e000