property演示用法

[python]代码库

# -*- coding: utf-8 -*-
'''请利用@property给一个Screen对象加上width和height属性，
以及一个只读属性resolution'''
class Screen(object):
    __slots__ = ('_width','_height')

    @property
    def width(self):
        return self._width
    @property
    def height(self):
        return self._height
    @property
    def resolution(self):
        if not self._width:
            raise ValueError('width is wrong!')
        if not self._height:
            raise ValueError('height is wrong!')
        else:
            return self._width*self._height
    @width.setter
    def width(self,value):
        self._width = value
    @height.setter
    def height(self,value):
        self._height = value
    
wh = Screen()
wh.width=10
wh.height=20
#wh.kuan=20  'Screen' object has no attribute 'kuan'
print('wh.width(10)',wh.width)
print('wh.height(20)',wh.height)
print('wh.resolution',wh.resolution)

s = Screen()
s.width = 1024
s.height = 768
print('resolution =', s.resolution)
if s.resolution == 786432:
    print('测试通过!')
else:
    print('测试失败!')