Cython implementation of the
provides high performance utility functions for iterables, functions,
toolz is a pure Python package that borrows heavily from contemporary
functional languanges. It is designed to interoperate seamlessly with other
libraries including itertools, functools, and third party libraries.
High performance functional data analysis is possible with builtin types
like list and dict, and user-defined data structures; and low memory
usage is achieved by using the iterator protocol and returning iterators
cytoolz implements the same API as toolz. The main differences are
that cytoolz is faster (typically 2-5x faster with a few spectacular
exceptions) and cytoolz offers a C API that is accessible to other
projects developed in Cython. Since toolz is able to process very
large (potentially infinite) data sets, the performance increase gained by
using cytoolz can be significant.
cytoolz supports Python 2.7+ and Python 3.4+ with a common codebase.
It is developed in Cython, but requires no dependecies other than CPython
and a C compiler. Like toolz, it is a light weight dependency.
toolz (and cytoolz) aims to be a repository for utility functions,
particularly those that come from the functional programming and list
processing traditions. We welcome contributions that fall within this scope
and encourage users to scrape their util.py files for functions that are
Please take a look at our issue pages for
for contribution ideas.