实现一个FIFO的dict

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

__author__ = 'Noiccy'
'''description:实现一个FIFO的dict'''

from collections import OrderedDict

class LastUpdatedOrderedDict(OrderedDict):
    """docstring for LastUpdatedOrderedDict"""
    def __init__(self, capacity):
        super(LastUpdatedOrderedDict, self).__init__()
        self.__capacity = capacity

    def __setitem__(self, key, value):
        containskey = 1 if key in self else 0
        if len(self) - containskey >= self.__capacity:
            last = self.popitem(last = False)   #False：FIFO方式，True：LIFO方式
            print('remove:', last)
        if containskey:
            del self[key]
            print('set:', (key, value))
        else:
            print('add:', (key, value))
        OrderedDict.__setitem__(self, key, value) #将元素存入dict

if __name__ == '__main__':
    fifo_dict = LastUpdatedOrderedDict(3)
    fifo_dict['x'] = 1
    fifo_dict['y'] = 2
    fifo_dict['x'] = 3
    fifo_dict['z'] = 1
    fifo_dict['t'] = 0
    print(fifo_dict)

参考链接：https://www.liaoxuefeng.com/wiki/0014316089557264a6b348958f449949df42a6d3a2e542c000/001431953239820157155d21c494e5786fce303f3018c86000