Funcy |Build Status| =====

A collection of fancy functional tools focused on practicality.

Inspired by clojure, underscore and my own abstractions. Keep reading to get an overview or read the docs <https://funcy.readthedocs.io/>_. Or jump directly to cheatsheet <https://funcy.readthedocs.io/en/stable/cheatsheet.html>_.

Works with Python 3.4+ and pypy3.

Installation

::

pip install funcy

Overview

Import stuff from funcy to make things happen:

.. code:: python

from funcy import whatever, you, need

Merge collections of same type (works for dicts, sets, lists, tuples, iterators and even strings):

.. code:: python

merge(coll1, coll2, coll3, ...) join(colls) merge_with(sum, dict1, dict2, ...)

Walk through collection, creating its transform (like map but preserves type):

.. code:: python

walk(str.upper, {'a', 'b'}) # {'A', 'B'} walk(reversed, {'a': 1, 'b': 2}) # {1: 'a', 2: 'b'} walk_keys(double, {'a': 1, 'b': 2}) # {'aa': 1, 'bb': 2} walk_values(inc, {'a': 1, 'b': 2}) # {'a': 2, 'b': 3}

Select a part of collection:

.. code:: python

select(even, {1,2,3,10,20}) # {2,10,20} select(r'^a', ('a','b','ab','ba')) # ('a','ab') select_keys(callable, {str: '', None: None}) # {str: ''} compact({2, None, 1, 0}) # {1,2}

Manipulate sequences:

.. code:: python

take(4, iterate(double, 1)) # [1, 2, 4, 8] first(drop(3, count(10))) # 13

lremove(even, [1, 2, 3]) # [1, 3] lconcat([1, 2], [5, 6]) # [1, 2, 5, 6] lcat(map(range, range(4))) # [0, 0, 1, 0, 1, 2] lmapcat(range, range(4)) # same flatten(nested_structure) # flat iter distinct('abacbdd') # iter('abcd')

lsplit(odd, range(5)) # ([1, 3], [0, 2, 4]) lsplit_at(2, range(5)) # ([0, 1], [2, 3, 4]) group_by(mod3, range(5)) # {0: [0, 3], 1: [1, 4], 2: [2]}

lpartition(2, range(5)) # [[0, 1], [2, 3]] chunks(2, range(5)) # iter: [0, 1], [2, 3], [4] pairwise(range(5)) # iter: [0, 1], [1, 2], ...

And functions:

.. code:: python

partial(add, 1) # inc curry(add)(1)(2) # 3 compose(inc, double)(10) # 21 complement(even) # odd allfn(isa(int), even) # iseven_int

one_third = rpartial(operator.div, 3.0) has_suffix = rcurry(str.endswith, 2)

Create decorators easily:

.. code:: python

@decorator def log(call): print(call.func.name, call.args) return call()

Abstract control flow:

.. code:: python

walk_values(silent(int), {'a': '1', 'b': 'no'}) # => {'a': 1, 'b': None}

@once def initialize(): "..."

with suppress(OSError): os.remove('some.file')

@ignore(ErrorRateExceeded) @limiterrorrate(fails=5, timeout=60) @retry(tries=2, errors=(HttpError, ServiceDown)) def someunreliableaction(...): "..."

class MyUser(AbstractBaseUser): @cached_property def public_phones(self): return self.phones.filter(public=True)

Ease debugging:

.. code:: python

squares = {tap(x, 'x'): tap(x * x, 'x^2') for x in [3, 4]} # x: 3 # x^2: 9 # ...

@print_exits def some_func(...): "..."

@log_calls(log.info, errors=False) @log_errors(log.exception) def somesuspiciousfunction(...): "..."

with print_durations('Creating models'): Model.objects.create(...) # ... # 10.2 ms in Creating models

And much more <https://funcy.readthedocs.io/>_.

Dive in

Funcy is an embodiment of ideas I explain in several essays:

• Why Every Language Needs Its Underscore <https://suor.github.io/blog/2014/06/22/why-every-language-needs-its-underscore/>_
• Functional Python Made Easy <https://suor.github.io/blog/2013/10/13/functional-python-made-easy/>_
• Abstracting Control Flow <https://suor.github.io/blog/2013/10/08/abstracting-control-flow/>_
• Painless Decorators <https://suor.github.io/blog/2013/11/03/painless-decorators/>_

• https://pypi.org/project/funcy-chain/
• https://pypi.org/project/funcy-pipe/

To run the tests using your default python:

::

pip install -r test_requirements.txt pytest

To fully run `tox` you need all the supported pythons to be installed. These are 3.4+ and PyPy3. You can run it for particular environment even in absense of all of the above::

tox -e py310 tox -e pypy3 tox -e lint

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