布隆过滤器 python 实现

by nick / On 2020年8月24日 / In 后端开发, 算法

from bitarray import bitarray 
import mmh3 

class BloomFilter: 
    def __init__(self, size, hash_num): 
        self.size = size 
        self.hash_num = hash_num 
        self.bit_array = bitarray(size) 
        self.bit_array.setall(0) 
    def add(self, s): 
        for seed in range(self.hash_num): 
            result = mmh3.hash(s, seed) % self.size 
            self.bit_array[result] = 1 
    def lookup(self, s): 
        for seed in range(self.hash_num): 
            result = mmh3.hash(s, seed) % self.size 
            if self.bit_array[result] == 0: 
                return "Nope" 
        return "Probably" 
bf = BloomFilter(500000, 7) 
bf.add("dantezhao") 
print (bf.lookup("dantezhao")) 
print (bf.lookup("yyj"))

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