fastbloom
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[](https://docs.rs/fastbloom-rs)
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[](https://crates.io/crates/fastbloom-rs)
[](https://pypi.org/project/fastbloom-rs/)
A fast [bloom filter](#BloomFilter) | [counting bloom filter](#countingbloomfilter) implemented by Rust for Rust and
Python!
Language: [简体中文](./docs/README.zh_cn.md)
- [setup](#setup)
- [Python](#python)
- [requirements](#requirements)
- [install](#install)
- [Rust](#rust)
- [Java](#java)
- [Examples](#examples)
- [BloomFilter](#bloomfilter)
- [Python](#python-1)
- [Rust](#rust-1)
- [CountingBloomFilter](#countingbloomfilter)
- [Python](#python-2)
- [Rust](#rust-2)
- [benchmark](#benchmark)
- [computer info](#computer-info)
- [add one str to bloom filter](#add-one-str-to-bloom-filter)
- [add one million to bloom filter](#add-one-million-to-bloom-filter)
- [check one contains in bloom filter](#check-one-contains-in-bloom-filter)
- [check one not contains in bloom filter](#check-one-not-contains-in-bloom-filter)
- [add one str to counting bloom filter](#add-one-str-to-counting-bloom-filter)
- [add one million to counting bloom filter](#add-one-million-to-counting-bloom-filter)
# setup
## Python
### requirements
```
Python >= 3.7
```
### install
Install the latest fastbloom version with:
```bash
pip install fastbloom-rs
```
## Rust
```toml
fastbloom-rs = "{latest}"
```
## Java
maven
```xml
io.github.yankun1992
fastbloom
{latest-version}
```
# Examples
## BloomFilter
A Bloom filter is a space-efficient probabilistic data structure, conceived by Burton Howard
Bloom in 1970, that is used to test whether an element is a member of a set. False positive
matches are possible, but false negatives are not.
**Reference**: Bloom, B. H. (1970). Space/time trade-offs in hash coding with allowable errors.
Communications of the ACM, 13(7), 422-426.
[Full text article](http://crystal.uta.edu/~mcguigan/cse6350/papers/Bloom.pdf)
### Python
basic usage
```python
from fastbloom_rs import BloomFilter
bloom = BloomFilter(100_000_000, 0.01)
bloom.add_str('hello')
bloom.add_bytes(b'world')
bloom.add_int(9527)
assert bloom.contains('hello')
assert bloom.contains(b'world')
assert bloom.contains(9527)
assert not bloom.contains('hello world')
```
build bloom filter from bytes or list
```python
from fastbloom_rs import BloomFilter
bloom = BloomFilter(100_000_000, 0.01)
bloom.add_str('hello')
assert bloom.contains('hello')
bloom2 = BloomFilter.from_bytes(bloom.get_bytes(), bloom.hashes())
assert bloom2.contains('hello')
bloom3 = BloomFilter.from_int_array(bloom.get_int_array(), bloom.hashes())
assert bloom3.contains('hello')
```
there are some bulk api for python to reduce ffi cost between python and rust
```python
bloom = BloomFilter(100_000_000, 0.01)
inserts = [1, 2, 3, 4, 5, 6, 7, 9, 18, 68, 90, 100]
checks = [1, 2, 3, 4, 5, 6, 7, 9, 18, 68, 90, 100, 190, 290, 390]
results = [True, True, True, True, True, True, True, True, True, True, True, True, False, False, False]
bloom.add_int_batch(inserts)
contains = bloom.contains_int_batch(checks)
assert contains == results
bloom.add_str_batch(list(map(lambda x: str(x), inserts)))
assert bloom.contains_str_batch(list(map(lambda x: str(x), checks))) == results
bloom.add_bytes_batch(list(map(lambda x: bytes(x), inserts)))
assert bloom.contains_bytes_batch(list(map(lambda x: bytes(x), checks))) == results
```
more examples at [py_tests](py_tests/test_bloom.py).
### Rust
```rust
use fastbloom_rs::{BloomFilter, FilterBuilder};
let mut bloom = FilterBuilder::new(100_000_000, 0.01).build_bloom_filter();
bloom.add(b"helloworld");
assert_eq!(bloom.contains(b"helloworld"), true);
assert_eq!(bloom.contains(b"helloworld!"), false);
```
more examples at [docs.rs](https://docs.rs/fastbloom-rs)
## CountingBloomFilter
A Counting Bloom filter works in a similar manner as a regular Bloom filter; however, it is
able to keep track of insertions and deletions. In a counting Bloom filter, each entry in the
Bloom filter is a small counter associated with a basic Bloom filter bit.
**Reference**: F. Bonomi, M. Mitzenmacher, R. Panigrahy, S. Singh, and G. Varghese, “An Improved
Construction for Counting Bloom Filters,” in 14th Annual European Symposium on
Algorithms, LNCS 4168, 2006
### Python
```python
from fastbloom_rs import CountingBloomFilter
cbf = CountingBloomFilter(1000_000, 0.01)
cbf.add('hello')
cbf.add('hello')
assert 'hello' in cbf
cbf.remove('hello')
assert 'hello' in cbf # because 'hello' added twice.
# If add same element larger than 15 times, then remove 15 times the filter will not contain the element.
cbf.remove('hello')
assert 'hello' not in cbf
```
A CountingBloomFilter has a four bits counter to save hash index, so when insert an
element repeatedly, the counter will spill over quickly. So, you can set
`enable_repeat_insert` to `False` to check whether the element has added.
if it has added, it will not add again. `enable_repeat_insert` default set to `True`.
```python
from fastbloom_rs import CountingBloomFilter
cbf = CountingBloomFilter(1000_000, 0.01, False)
cbf.add('hello')
cbf.add('hello') # because enable_repeat_insert=False, this addition will not take effect.
assert 'hello' in cbf
cbf.remove('hello')
assert 'hello' not in cbf
```
more examples at [py_tests](py_tests/test_counting_bloom_filter.py).
### Rust
```rust
use fastbloom_rs::{CountingBloomFilter, FilterBuilder};
let mut builder = FilterBuilder::new(100_000, 0.01);
let mut cbf = builder.build_counting_bloom_filter();
cbf.add(b"helloworld");
assert_eq!(bloom.contains(b"helloworld"), true);
```
# benchmark
## computer info
| CPU | Memory | OS |
|----------------------------------------|--------|------------|
| AMD Ryzen 7 5800U with Radeon Graphics | 16G | Windows 10 |
## add one str to bloom filter
Benchmark insert one str to bloom filter:
```text
bloom_add_test time: [41.168 ns 41.199 ns 41.233 ns]
change: [-0.4891% -0.0259% +0.3417%] (p = 0.91 > 0.05)
No change in performance detected.
Found 13 outliers among 100 measurements (13.00%)
1 (1.00%) high mild
12 (12.00%) high severe
```
## add one million to bloom filter
Benchmark loop insert `(1..1_000_000).map(|n| { n.to_string() })` to bloom filter:
```text
bloom_add_all_test time: [236.24 ms 236.86 ms 237.55 ms]
change: [-3.4346% -2.9050% -2.3524%] (p = 0.00 < 0.05)
Performance has improved.
Found 5 outliers among 100 measurements (5.00%)
4 (4.00%) high mild
1 (1.00%) high severe
```
## check one contains in bloom filter
```text
bloom_contains_test time: [42.065 ns 42.102 ns 42.156 ns]
change: [-0.7830% -0.5901% -0.4029%] (p = 0.00 < 0.05)
Change within noise threshold.
Found 15 outliers among 100 measurements (15.00%)
1 (1.00%) low mild
5 (5.00%) high mild
9 (9.00%) high severe
```
## check one not contains in bloom filter
```text
bloom_not_contains_test time: [22.695 ns 22.727 ns 22.773 ns]
change: [-3.1948% -2.9695% -2.7268%] (p = 0.00 < 0.05)
Performance has improved.
Found 12 outliers among 100 measurements (12.00%)
4 (4.00%) high mild
8 (8.00%) high severe
```
## add one str to counting bloom filter
```text
counting_bloom_add_test time: [60.822 ns 60.861 ns 60.912 ns]
change: [+0.2427% +0.3772% +0.5579%] (p = 0.00 < 0.05)
Change within noise threshold.
Found 10 outliers among 100 measurements (10.00%)
1 (1.00%) low severe
4 (4.00%) low mild
1 (1.00%) high mild
4 (4.00%) high severe
```
## add one million to counting bloom filter
Benchmark loop insert `(1..1_000_000).map(|n| { n.to_string() })` to counting bloom filter:
```text
counting_bloom_add_million_test
time: [272.48 ms 272.58 ms 272.68 ms]
Found 2 outliers among 100 measurements (2.00%)
1 (1.00%) low mild
1 (1.00%) high mild
```