带有对象列表的Python min函数

Question

如何使用函数的key参数min来比较对象的1属性列表？

例

class SpecialNumber:
    def __init__(self, i):
        self.number = i

li = [SpecialNumber(1), SpecialNumber(3), SpecialNumber(2)]

Answer 1

http://docs.python.org/library/operator.html#operator.attrgetter

from operator import attrgetter
min_num = min(li,key=attrgetter('number'))

互动会话示例：

>>> li = [SpecialNumber(1), SpecialNumber(3), SpecialNumber(2)]
>>> [i.number for i in li]
[1, 3, 2]
>>> min_num = min(li,key=attrgetter('number'))
>>> print min_num.number
1