Bloomfilter sample

bloomfilter.py

#!/usr/bin/python
import hashlib

startKey = 2
endKey = 6
inputNum = 1000
testNum = 100000

def check_bl(bloom, a):
    aa = hashlib.md5(a).hexdigest()[startKey:endKey]
    ab = hashlib.sha1(a).hexdigest()[startKey:endKey]
    ac = hashlib.sha256(a).hexdigest()[startKey:endKey]
    ad = hashlib.sha224(a).hexdigest()[startKey:endKey]
    if bloom.get(aa, 0) == 1 \
            and bloom.get(ab, 0) == 1 \
            and bloom.get(ac, 0) == 1 \
            and bloom.get(ad, 0) == 1:
        return True
    return False

def bl(bloom, a):
    bloom[hashlib.md5(a).hexdigest()[startKey:endKey]] = 1
    bloom[hashlib.sha1(a).hexdigest()[startKey:endKey]] = 1
    bloom[hashlib.sha256(a).hexdigest()[startKey:endKey]] = 1
    bloom[hashlib.sha224(a).hexdigest()[startKey:endKey]] = 1

def initialize(bloom):
    for i in xrange(inputNum):
            bl(bloom, 'd' + str(i))

def testBloom(bloom):
    count = 0
    for i in xrange(inputNum, inputNum + testNum):
           if check_bl(bloom, 'a' + str(i)):
               print "%s is false positive" % ('a' + str(i),)
               count += 1
    print "false positive count: %d" % (count,)

def main():
    bloom = {}
    initialize(bloom)
    testBloom(bloom)




if __name__=='__main__':
    main()