Alakazam is an open-source Python library which adds convenient syntax for functional programming stream operations to Python.

Python already supports the basic operations needed to perform functional-style streaming operations: those being map, filter, and functools.reduce. However, these operations have the unfortunate side effect of being written in the opposite than one would read the code. Consider the following snippet.

list(filter(lambda x: x: x % 2 == 0, map(lambda x: x ** 2, arr)))

The logic of this code is as follows. Take an input list arr, square each element, and then keep only the even values, producing a new list as output. But the code reads in reverse: produce a list, which is the result of filtering to keep only the even values, from the result of squaring each element of the input list arr

Alakazam introduces a new datatype, appropriately called Alakazam, which defines map and filter as instance methods that can be called in a more OOP-style. The above code snippet, in Alakazam, is as follows.

import alakazam as zz

zz.of(arr).map(lambda x: x ** 2).filter(lambda x: x % 2 == 0).list()

In fact, Alakazam pretties up the Python lambda syntax as well. For lambdas that only use Python operators, such as the modulo, equals sign, and exponentiation operators in this example, we can use a Boost-style syntax to build the lambda, rather than having to write it out explicitly.

import alakazam as zz
from alakazam import _1

zz.of(arr).map(_1 ** 2).filter(_1 % 2 == 0).list()

The Alakazam class provides over 70 helper methods, adapting all of Python's built-in streaming functions, as well as all of itertools. Alakazam smooths out some of the corner cases of these functions and additionally provides some useful list streaming operations from Haskell that are not native to Python.

Alakazam can be installed with pip. It works on all versions of Python 3, as well as Python 2.6 and newer, and it has no additional dependencies.