algorithm-in-python/search/bloomFilter.py

''' mbinary
#########################################################################
# File : bloomFilter.py
# Author: mbinary
# Mail: zhuheqin1@gmail.com
# Blog: https://mbinary.xyz
# Github: https://github.com/mbinary
# Created Time: 2018-10-17  11:19
# Description:
#########################################################################
'''
from bitarray import bitarray

import mmh3


class bloomFilter(set):
    def __init__(self, size, hash_count):
        super(bloomFilter, self).__init__()
        self.bits = bitarray(size)
        self.bits.setall(0)
        self.size = size
        self.hash_count = hash_count

    def __len__(self):
        return self.size

    def __iter__(self):
        return iter(self.bits)

    def add(self, item):
        for i in range(self.hash_count):
            idx = mmh3.hash(item, i) % self.size
            self.bits[idx] = 1
        return self

    def __contains__(self, item):
        idxs = [mmh3.hash(item, i) % self.size for i in range(self.hash_count)]
        return all([self.bits[i] == 1 for i in idxs])