hiway / python-bloom-filter

Bloom filter for Python

Note: This project has gone unmaintained for a while, please use the more up-to-date project at:

• https://github.com/remram44/python-bloom-filter
• https://pypi.org/project/bloom-filter2/

bloom-filter

This project builds on drs-bloom-filter and bloom_filter_mod. Credits and links can be found in AUTHORS.md.

Installation

pip install bloom_filter

Example:

from bloom_filter import BloomFilter

have_met = BloomFilter()

def have_i_met(name):
    met = name in have_met
    print('Have I met {} before: {}'.format(name, met))

def meet(name):
    have_met.add(name)
    print('Hello, {}'.format(name))

for name in ['Harry', 'Larry', 'Moe']:
    have_i_met(name)
    meet(name)
    have_i_met(name)

Usage:

from bloom_filter import BloomFilter

# instantiate BloomFilter with custom settings,
# max_elements is how many elements you expect the filter to hold.
# error_rate defines accuracy; You can use defaults with
# `BloomFilter()` without any arguments. Following example
# is same as defaults:
bloom = BloomFilter(max_elements=10000, error_rate=0.1)

# Test whether the bloom-filter has seen a key:
assert "test-key" in bloom is False

# Mark the key as seen
bloom.add("test-key")

# Now check again
assert "test-key" in bloom is True