`fz` 0.1

Quick and efficient lambda functions.

What is `fz`?

fz provides a nicer way to define lambda functions for Python 3. The syntax is inspired by C++ std::bind, Scala lambdas, and quicklambda <https://github.com/abarnert/quicklambda>_ for python.

Syntax

fz lambdas use placeholder objects to represent the arguments to the new lambda. The placeholders look like: _1, _2, ..., all the way to _255 (the maximum number of positional arguments to a function).

To create a lambda, just build up an expression using these placeholders where you want the arguments to go.

Example Uses

Simple Arithmetic


Many lambdas are just simple arithmetic. For example:

.. code-block:: python

   >>> from fz import _1
   >>> f = _1 + 1
   >>> f(1)
   2
   >>> f(3)
   4
   >>> (_1 * 2)(3)
   6
   >>> (_1 ** 2)(3)
   9
   >>> list(map(_1 ** 2, range(5)))
   [0, 1, 4, 9, 16]


Attribute and Item Access

.. code-block::

from fz import _1

_1[0]([1, 2]) 1 list(map(_1[1], [(0, 1), (2, 3), (4, 5)])) [1, 3, 5] _1.imag(1j) 1.0 list(map(_1.imag, (1j, 1 + 2j, 2 + 3j))) [1, 2, 3]

Function Calls


Because we can only wrap things top-down, we must explicitly wrap a function
to be defered.

.. code-block:: python

   >>> from fz import _f, _1, _2, _3
   >>> def f(a, b):
   ...     return a + b
   >>> _f(f)(_1, _2)(1, 2)
   3
   >>> g = _f(f)(_1, -1)
   >>> g(1)
   0

   >>> flip = _f(_1)(_3, _2)
   >>> flip(print, 1, 2)
   2 1


Supported Operations