File size: 4,881 Bytes
d40299b | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 | Funcy |Build Status| |Gitter|
=====
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 <http://funcy.readthedocs.org/>`_.
Or jump directly to `cheatsheet <http://funcy.readthedocs.io/en/stable/cheatsheet.html>`_.
Works with Python 2.7, 3.4+ and pypy.
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
all_fn(isa(int), even) # is_even_int
one_third = rpartial(operator.div, 3.0)
has_suffix = rcurry(str.endswith)
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)
@limit_error_rate(fails=5, timeout=60)
@retry(tries=2, errors=(HttpError, ServiceDown))
def some_unreliable_action(...):
"..."
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 some_suspicious_function(...):
"..."
with print_durations('Creating models'):
Model.objects.create(...)
# ...
# 10.2 ms in Creating models
And `much more <http://funcy.readthedocs.org/>`_.
Dive in
-------
Funcy is an embodiment of ideas I explain in several essays:
- `Why Every Language Needs Its Underscore <http://hackflow.com/blog/2014/06/22/why-every-language-needs-its-underscore/>`_
- `Functional Python Made Easy <http://hackflow.com/blog/2013/10/13/functional-python-made-easy/>`_
- `Abstracting Control Flow <http://hackflow.com/blog/2013/10/08/abstracting-control-flow/>`_
- `Painless Decorators <http://hackflow.com/blog/2013/11/03/painless-decorators/>`_
Running tests
--------------
To run the tests using your default python:
::
pip install -r test_requirements.txt
py.test
To fully run ``tox`` you need all the supported pythons to be installed. These are
2.6+, 3.3+, PyPy and PyPy3. You can run it for particular environment even in absense
of all of the above::
tox -e py27
tox -e py36
tox -e lint
.. |Build Status| image:: https://travis-ci.org/Suor/funcy.svg?branch=master
:target: https://travis-ci.org/Suor/funcy
.. |Gitter| image:: https://badges.gitter.im/JoinChat.svg
:alt: Join the chat at https://gitter.im/Suor/funcy
:target: https://gitter.im/Suor/funcy?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge
|