Python Learning note __7.2 using @property

# This is a learning note for the Liaoche teacher Python tutorial

1. Overview

@property Allows you to call "method" as "property"

# method source Code

Class Student (object):

def get __ score (self):

Return Self.__score

def set __ score (self, value):

If not isinstance (value, int):

Raise ValueError (' score must is an integer! ')

If value < 0 or value > 100:

Raise ValueError (' score must between 0 ~ 100! ')

Self.__score = value

# Add @property

Class Student (object):

@property    # @property : Turns a getter method into a property

DEF score (self):

Return Self.__score

@score. Setter #  @score. Setter : Put a Setter method becomes a property

DEF score (self, value):

If not isinstance (value, int):

Raise ValueError (' score must is an integer! ')

If value < 0 or value > 100:

Raise ValueError (' score must between 0 ~ 100! ')

Self.__score = value

Attention:

2. the two methods defined above score , in the past @property and the @score. Setter , it becomes a score property.

4. The function name is not very meaningful here, it is just for the sake of conversion to properties after we call.

6. through dir () , compared with two code instance , it is easy to see how the changes to the properties

8. used a @property after, can not be arbitrarily to instance Add Property Now .

Like the code above. S.name= ' Bart ', will be an error.

2. Example

1 , please use @property to a Screen Object Plus width and the Height property, and a read-only property resolution :

#-*-Coding:utf-8-*-

Class screen (object):

@property

def width (self):

Return __width

@width. Setter

def width (self,value):

Self.__width=value

@property

def height (self):

Return __height

    @ height. Setter

def height (self,value):

Self.__height=value

@property

def resolution (self):

Self.__resolution=self.__width * Self.__height

Return self.__resolution

Test
s = screen ()
S.width = 1024
S.height = 768
Print (' Resolution = ', s.resolution)
if s.resolution = = 786432:
Print (' Test pass! ')
Else
Print (' Test failed! ' ) )

Python Learning note __7.2 using @property