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 (not complete yet).
pip install funcy
Just import stuff from funcy to make things happen:
from funcy import * # or whatever you need
Merge collections of same type (works for dicts, sets, lists, tuples, iterators and even strings):
merge(coll1, coll2, coll3, ...)
join(colls)
Walk through collection, creating it's transform (like map but preserves type):
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:
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, '', 0}) # {2,'',0}
Test collection contents:
all(callable, [abs, open, int]) # True
all(even, [1, 2, 5]) # False
any(even, [1, 2, 5]) # True
none(even, [1, 2, 5]) # False
is_distinct('adbec') # True
Or search for something:
some(even, [1, 2, 5]) # 2
some([0, '', -1, None, 2]) # -1
More tools for mappings:
flip({'a': 1, 'b': 2}) # {1: 'a', 2: 'b'}
project({'a': 1, 'b': 2, 'c': 3}, ['a', 'c']) # {'a': 1, 'c': 3}
pluck('a', [{'a': 1, 'b': 2}, {'a': 10}]) # [1, 10]
where([{'a': 1, 'b': 2}, {'a': 10}], a=1) # [{'a': 1, 'b': 2}]
Manipulate functions:
partial(add, 1) # inc
curry(add)(1)(2) # 3
compose(inc, double)(10) # 21
complement(even) # odd
map(iffy(len), ['ab',None,'c'] # [2,None,1]
iffy(callable, caller())(val) # val() if callable(val) else val
Easy decorators:
@decorator
def log(call):
print call._func.__name__, call._args
return call()
Work with sequences:
take(4, iterate(double, 1)) # [1, 2, 4, 8]
first(drop(3, count(10))) # 13
remove(even, [1, 2, 3]) # [1, 3]
concat([1, 2], [5, 6]) # [1, 2, 5, 6]
cat(map(range, range(4))) # [0, 0, 1, 0, 1, 2]
mapcat(range, range(4))) # same
distinct('abacbdd') # list('abcd')
split(odd, range(5)) # [[1, 3], [0, 2, 4]]
split_at(2, range(5)) # [[0, 1], [2, 3, 4]]
group_by(mod3, range(5)) # {0: [0, 3], 1: [1, 4], 2: [2]}
partition(2, range(5)) # [[0, 1], [2, 3]]
chunks(2, range(5)) # [[0, 1], [2, 3], [4]]
partition(2, 1, range(4)) # [[0, 1], [1, 2], [2, 3]]
chunks(2, 1, range(4)) # [[0, 1], [1, 2], [2, 3], [3]]
And many more.
Bring your ideas and/or code that can make functional python more fun.
- create cheatsheet html
- reject*(), disjoint*() collections
- merge_with(), zip_with()
- starfilter()
- one argument select*()? other name?
- distinct() to work with unhashable values, id_func?
- reversed() to work with iterators?
- vector chained boolean test (like perl 6 [<])