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Python __getattr__与__setattr__使用方法

程序员文章站 2022-04-27 10:38:00
比如下面的例子: class book(object):    def __setattr__(self, name, value):&nb...
比如下面的例子:
class book(object):
    def __setattr__(self, name, value):
        if name == 'value':
            object.__setattr__(self, name, value - 100)
        else:
            object.__setattr__(self, name, value)
    def __getattr__(self, name):
        try:
            return object.__getattribute__(name)
        except:
            return name + ' is not found!'
    def __str__(self):
        return self.name + ' cost : ' + str(self.value)

c = book()
c.name = 'python'
c.value = 100
print c.name
print c.value
print c
print c.type


上面的例子中,在赋值书的value属性时,偷偷的将value减去了100,呵。输出结果:

python
0
python cost : 0
type is not found!