python实现简单的LRU(Least Recently Used)

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LRU通常在讲操作系统分页置换的方法中提及，但其实他还是种很好的内存调度算法。

PyPI和网上有各种版本，但觉得都略复杂，因此写个简化版。

# -*- coding: utf-8 -*-from collections import OrderedDict__all__ = ['LRUCache', ]class LRUCache(dict):    '''简单lru队列实现'''    def __init__(self, size = None):        self.buff_size = 100 if size is None else size        self.__cache = OrderedDict()            def __getitem__(self, *args, **kwargs):        _key = args[0]        if _key in self.__cache:            self.__cache[_key] = self.__cache.pop(_key)        return self.__cache.get(_key, None)        def __setitem__(self, *args, **kwargs):        _key, _value = args        if _key in self.__cache:            self.__cache.pop(_key)        elif self.buff_size == len(self.__cache):            self.__cache.popitem(last = False)        self.__cache[_key] = _value            def __contains__(self, *args, **kwargs):        return self.__cache.__contains__(*args, **kwargs)            def __delitem__(self, *args, **kwargs):        return self.__cache.__delitem__(*args, **kwargs)            def __repr__(self, *args, **kwargs):        return dict(self.__cache).__repr__(*args, **kwargs)        def items(self, *args, **kwargs):        return self.__cache.items(*args, **kwargs)        def values(self, *args, **kwargs):        return self.__cache.values(*args, **kwargs)        def keys(self, *args, **kwargs):        return self.__cache.keys(*args, **kwargs)        if __name__ == '__main__':    test_cache = LRUCache(3)    for num in range(5):        test_cache[num] = num    print(test_cache)

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