1、优点,方便删除记录,直接处理数组对应下标的子数组。平均搜索速度快。如果有冲突,只需要查询子数组。
2、缺点,使用指针导致查询速度较慢,内存占用可能较高,不适合序列化。
而开放式寻址法的优缺点与链表法相反。因为Python的一切都是基于Dict的,都需要序列化,所以选择了开放式寻址法。
python链表法实例
# keys函数 #!/usr/bin/env python # coding=utf-8 class Dict: def __init__(self, num): self.__solts__ = [] self.num = num for _ in range(num): self.__solts__.append([]) def hash_fun(self,key,num): hashval = 0 x = key if x < 0: print "the key is low" return while x != 0: hashval = (hashval << 3) + x%10 x /=10 return hashval % num def put(self, key, value): i = self.hash_fun(key,self.num) % self.num for p, (k, v) in enumerate(self.__solts__[i]): if k == key: break else: self.__solts__[i].append((key, value)) return self.__solts__[i][p] = (key, value) def get(self, key): i = self.hash_fun(key,self.num) % self.num for k, v in self.__solts__[i]: if k == key: return v raise KeyError(key) # keys函数 def keys(self): ret = [] for solt in self.__solts__: for k, _ in solt: ret.append(k) return ret def __getitem__(self,key): return self.get(key) def __setitem__(self,key,data): self.put(key,data) H = Dict(13) H[54] = "cat" H[26] = "dog" H[93] = "lion" H[17] = "tiger" H[77] = "bird" H[31] = "cow" H[44] = "goat" H[55] = "pig" H[20] = "chicken" print H.get(54) H.put(13,"duck") print H.__solts__ print H.keys()
以上就是python链表法的优缺点,希望对大家有所帮助。
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