cityhash 0.2.4.post9

Python bindings for CityHash, a fast non-cryptographic hash algorithm

A Python wrapper around CityHash

Getting Started

To use this package in your program, simply type

pip install cityhash

After that, you should be able to import the module and do things with it (see usage example below).

Usage Examples

Simple Hashing

The package contains 64- and 128-bit implementations of the CityHash algorithm, named as follows:

>>> from cityhash import CityHash32, CityHash64, CityHash128
>>> print(CityHash32("abc"))
795041479
>>> print(CityHash64("abc"))
2640714258260161385
>>> print(CityHash128("abc"))
76434233956484675513733017140465933893

Incremental Hashing

The current implementation of CityHash does not support incremental hashing. If you require this feature, use MetroHash instead, which does support it.

Buffer Protocol Support

The methods in this module support Python Buffer Protocol, which allows them to be used on any object that exports a buffer interface. Here is an example showing hashing of a 4D NumPy array:

>>> import numpy as np
>>> arr = np.zeros((256, 256, 4))
>>> CityHash64(arr)
11496798039784891892

Note that arrays need to be contiguous for this to work. To convert a non-contiguous array, use np.ascontiguousarray() method.

Development

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

git clone https://github.com/escherba/python-cityhash.git
cd python-cityhash
make env           # creates a Python virtualenv
make test          # run Python tests
make cpp-test      # run C++ tests

The Makefiles provided have self-documenting targets. To find out which targets are available, type:

make help

See Also

For other fast non-cryptographic hashing implementations available as Python extensions, see MetroHash and xxHash.

Authors

The Python bindings were originally written by Alexander [Amper] Marshalov, then repackaged for PyPI (with minor improvements) by Eugene Scherba. The original CityHash algorithm is by Google.

License

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