property-examples.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

__author__ = 'Administrator'

class Screen(object):

    @property
    def width(self):
        return self._width

    @width.setter
    def width(self, value):
        if not isinstance(value, int):
            raise ValueError('width must be an integer!')
        self._width = value

    @property
    def height(self):
        return  self._height

    @height.setter
    def height(self, value):
        if not isinstance(value, int):
            raise ValueError('height must be an integer!')
        self._height = value

    @property
    def resolution(self):
        return self._height * self._width


#test
s = Screen()
s.width = 1024
s.height = 768
print(s.resolution)
assert  s.resolution == 786432, '1024 * 768 = %d ?' % s.resolution