algorithm-in-python/search/bloomFilter.py

40 lines
1.0 KiB
Python

''' 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])