Skip to main content

Python bindings for CityHash and FarmHash

Project description


Python wrapper for FarmHash and CityHash, a family of fast non-cryptographic hash functions.

Build Status Latest Version Downloads License Supported Python versions

Getting Started

This simplest way to use this package is to install it from PyPI:

pip install cityhash

This package exposes Python APIs for CityHash and FarmHash under cityhash and farmhash namespaces, respectively. Each provides 32-, 64- and 128-bit implementations.

Usage Examples

Stateless hashing

Usage example for FarmHash:

>>> from farmhash import FarmHash32, FarmHash64, FarmHash128
>>> FarmHash32("abc")
>>> FarmHash64("abc")
>>> FarmHash128("abc")

Hardware-independent fingerprints

Fingerprints are seedless hashes which are guaranteed to be hardware- and platform-independent. This can be useful for networking applications which require persisting hashed values.

>>> from farmhash import Fingerprint128
>>> Fingerprint128("abc")

Incremental hashing

CityHash and FarmHash do not support incremental hashing and thus are not ideal for hashing of streams. If you require incremental hashing feature, use MetroHash or xxHash instead, which do support it.

Fast hashing of NumPy arrays

The Python Buffer Protocol allows Python objects to expose their data as raw byte arrays to other objects, for fast access without copying to a separate location in memory. Among others, NumPy is a major framework that supports this protocol.

All hashing functions in this packege will read byte arrays from objects that expose them via the buffer protocol. Here is an example showing hashing of a 4D NumPy array:

>>> import numpy as np
>>> from farmhash import FarmHash64
>>> arr = np.zeros((256, 256, 4))
>>> FarmHash64(arr)

The arrays need to be contiguous for this to work. To convert a non-contiguous array, use NumPy's ascontiguousarray() function.

SSE4.2 support

For x86-64 platforms, the PyPi repository for this package includes wheels compiled with SSE4.2 support. The 32- and 64-bit FarmHash variants significantly benefit from SSE4.2 instructions. The 128-bit version, unfortunately, does not exhibit speed up after compiling with SSE4.2 support.

The vanilla CityHash fucntions (under cityhash module) do not take advantage of SSE4.2. Instead, the cityhashcrc module provided with this package exposes 128- and 256-bit CRC functions which do harness SSE4.2. These functions are very fast, and beat FarmHash128 on speed (FarmHash does not include a 256-bit function). Since FarmHash is the intended successor of CityHash, I would be careful before using the CityHash-CRC functions, however, and would verify whether they provide sufficient randomness for your intended application.


Local workflow

For those who want to contribute, here is a quick start using some makefile commands:

git clone
cd python-cityhash
make env           # create a virtual environment
make test          # run Python tests
make cpp-test      # run C++ tests
make shell         # enter IPython shell

To find out which Make targets are available, type:

make help


The wheels are built using cibuildwheel and are distributed to PyPI using GitHub actions. The wheels contain compiled binaries and are available for the following platforms: windows-amd64, ubuntu-x86, linux-x86_64, linux-aarch64, and macosx-x86_64.

See Also

For other fast non-cryptographic hash functions available as Python extensions, see MetroHash, MurmurHash, and xxHash.


The original CityHash Python bindings are due to Alexander [Amper] Marshalov. These were rewritten in Cython by Eugene Scherba, who also added the FarmHash bindings. The CityHash and FarmHash algorithms and their C++ implementation are by Google.


This software is licensed under the MIT License. See the included LICENSE file for details.

Project details

Release history Release notifications | RSS feed

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

cityhash-0.4.6.tar.gz (216.0 kB view hashes)

Uploaded source

Built Distributions

cityhash-0.4.6-cp311-cp311-win_amd64.whl (55.0 kB view hashes)

Uploaded cp311

cityhash-0.4.6-cp311-cp311-win32.whl (61.2 kB view hashes)

Uploaded cp311

cityhash-0.4.6-cp310-cp310-win_amd64.whl (54.6 kB view hashes)

Uploaded cp310

cityhash-0.4.6-cp310-cp310-win32.whl (60.5 kB view hashes)

Uploaded cp310

cityhash-0.4.6-cp39-cp39-win_amd64.whl (55.4 kB view hashes)

Uploaded cp39

cityhash-0.4.6-cp39-cp39-win32.whl (61.0 kB view hashes)

Uploaded cp39

cityhash-0.4.6-cp38-cp38-win_amd64.whl (55.5 kB view hashes)

Uploaded cp38

cityhash-0.4.6-cp38-cp38-win32.whl (61.2 kB view hashes)

Uploaded cp38

cityhash-0.4.6-cp37-cp37m-win_amd64.whl (55.5 kB view hashes)

Uploaded cp37

cityhash-0.4.6-cp37-cp37m-win32.whl (60.9 kB view hashes)

Uploaded cp37

cityhash-0.4.6-cp36-cp36m-win_amd64.whl (55.4 kB view hashes)

Uploaded cp36

cityhash-0.4.6-cp36-cp36m-win32.whl (60.8 kB view hashes)

Uploaded cp36

Supported by

AWS AWS Cloud computing Datadog Datadog Monitoring Facebook / Instagram Facebook / Instagram PSF Sponsor Fastly Fastly CDN Google Google Object Storage and Download Analytics Huawei Huawei PSF Sponsor Microsoft Microsoft PSF Sponsor NVIDIA NVIDIA PSF Sponsor Pingdom Pingdom Monitoring Salesforce Salesforce PSF Sponsor Sentry Sentry Error logging StatusPage StatusPage Status page