import toolz
import poser
from poser import λ, Λ, stars
[](https: // github.com/deathbeds/poser/actions)
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a functional swiss army knife for python. poser provides python objects you didn't know you needed.
poser is a API for lazy, (dys)functional python programming. It allows complex functions to be composed using fluent or symbollic interfaces.
pip install poserdysfunctional programming == = Functional programming with all the side effects.
New to[functional programming]? Functional programming uses declarative functions to compose complex operations on arguments.
If you are familiar with python then[toolz][toolz] is a great starting point, [poser][poser] is a compact[API] for [toolz] and the python
[standard library].
poser
λ is a composition that always returns a function. For example, below we create a list of numbers from 1 to a some value
f = λ.range(1).list() f λ(< class 'list' > , functools.partial( < class 'range' > , 1)) >> > assert callable(f) >> > f(5), f(10) ([1, 2, 3, 4], [1, 2, 3, 4, 5, 6, 7, 8, 9])
poser can use forward references to lazily import modules.
g = λ.range(1).enumerate().dict()['pandas.Series'] g λ(ForwardRef('pandas.Series'), < class 'dict' > , < class 'enumerate' > , functools.partial(< class 'range' > , 1)) >> > λ(9) + g + type + ... <class 'pandas.core.series.Series' >
Λ is for object function composition where the
function represents symbollic or chained methods
(Λ10+2)(1) 12 assert (Λ10+2)(1) == 1*10+2 s = "A formatted string :{}: with a %s" ... (Λ.format('foo') % '% formatted').upper()(s) 'A FORMATTED STRING :FOO: WITH A % FORMATTED'
assert (Λ.format('foo') % '% formatted').upper()(s)
... == (s.format('foo') % '% formatted').upper()
The poser API expresses all of the symbols in the python data model. Refer to the tests for examples.
assert isinstance(λrange, type, str, tuple) assert isinstance(λ[range, type, str], list) assert isinstance(λ{range, type, str}, set)
Value and keyword functions can be supplied to juxtapose functions across dictionaries.
λ{'a': range, type: str} {'a': range(0, 10), int: '10'}
get = λ'functools.lru_cache'( λ['requests.get'][λ[Λ.json()] ^ BaseException | Λ.text()]) get
read = λ**Λ.startswith('http') & get | λ.Path().read_text()