lully 3.3.0

Helpers and utils

Lully

A small library providing some helpers for python devs.

See the tests for usage examples and ideas.

Popglobal

Populate global with cabalistic aliases and some of lully's objects.

import lully as ll
ll.popglob()  # use show=True to get a list of added values


ı('a', 'b', 'c')
i(['a', 'b', 'c'])
ï()

assert first('ab') == 'a'
assert last('ab') == 'b'
assert last('ab') == 'b'

Will do this automatically in REPL mode if you import lully, and if LULLY_DISABLE_REPL is not set to 1.

Funcmore

More tools for functions, notably lully.ẍ, that create a function out of two (or more):

import lully as ll
ll.ẍ(print, input)('$ ')  # --> print(input('$ '))
ll.ẍ(''.join, lambda v: v.split())('h e l l o')  # --> 'hello'
ll.ẍ(print, list)('hello')  # --> print(list('hello')) --> ['h', 'e', 'l', 'l', 'o']

And lully.ÿ that do the same thing, but splat the output in next function calls :

ll.ÿ(print, list)('hello')  # --> print(*list('hello')) --> h e l l o

Collections

Otom

The One-To-One-Mapping is a special kind of dict, where all values are also keys, associated to their key.

from lully import Otom

O = Otom({
    'one': 1,
    'two': 2,
    'tee': 3,
})
assert O[1] == 'one'
assert O['one'] == 1

An Otom acts like a dict. See tests for more.

Transformations

Date utils

Many functions, like time_since, time_from_now, pretty_seconds, parse_date, now_plus, add_time, parse_isoformat_with_microseconds may help dealing with (un)aware datetimes, relative times, and various date format.

Human-readable hashing

You may get a string like Pieuvre Minérale out of any python object with lully.human_code.

Confiseur

A Confiseur is here to help with configurations.

The principle is to subclass, for each configuration kind you need, the Confiseur base class and populate it with Bonbon instances, describing options.

from lully import Confiseur, Bonbon

class MyConfig(Confiseur):

    def bonbons(self) -> [Bonbon]:
        return (
            Bonbon('server options', 'max instances', default=3),
        )

    def validate(self, cfg):
        if cfg['server options']['max instances'] > 10:
            self.add_error(f"Can't handle more than ten instances. Provided: {cfg['server options']['max instances']}.")

myconfig = MyConfig('{"server options": { "max instances": 11 }}')
assert myconfig['server options']['max instances'] == 11
assert myconfig.has_error
assert len(myconfig.errors)

See tests for more.

Itermore

More itertools functions !

from lully.itermore import window, grouper, flatten, dotproduct, ncycles

See the source file for the full set of functions.

Kotlin-inspired functions

When coding in other languages, you get ideas. Here are the ones i got after a 1h course of Kotlin.

from lully import first, last, zip_with_next

assert first([1, 2]) == 1
assert last([1, 2]) == 2
assert first([2, 3], lambda x: x % 2) == 3
assert tuple(zip_with_next('abc')) == (('a', 'b'), ('c', None))

See the source file for the full set of functions.

Fief

This name should recall both its goal, which is FIltering of EFfective paramaters, and the fact it keeps functions to work within their fief.

You have this function:

def func(a, b):
    ...  # some implementation

and you have its parameter stored in a dict, with other keys that are not for that specific function:

config = {'a': 1, 'b': 'doe', 'loglevel': 'WARNING'}

Thus, you can't just do that:

func(**config)

Because of the expected:

TypeError: func() got an unexpected keyword argument 'loglevel'

One solution can be to filter that dict, but that's cumbersome and needs maintainance. And that's worse if you have a lot of functions to call that way.

Fief is a decorator that will make that for you, using inspect module.

from lully import fief

@fief
def func(a, b):
    return a + b

config = {'a': 2, 'b': 3, 'loglevel': 'WARNING'}

# and suddenly, you can provide anything in keywords argument:
assert func(**config) == 5   # no TypeError, that's magic !

random

lsample

This is a function answering to the n choose k problem using the Vitter's algorithm.

The problem is to choose randomly n element in a set of k. That's usually done with the random.sample(n, [1, 2, ...]) function. Hence the sampling part of lsample name. However, that stdlib function will load everything in memory, forcing you to provide a list, not a generator.

Vitter's solution is to collect the n elements during a single pass over the list, making possible to work on generators, as long as you have an idea of their size, hence not loading all data in memory.

from lully import lsample
print(lsample(3, [x for x in range(10)], it_size=10))

This enables you to pick 100 random tweets among the entire tweeter database without having to load it in memory. Provided you have enough time for the full browsing to be performed.

See that repo for more information, sources and benchmarks.

Logging

The generic lully.logger_from(o) will help you getting a logger, whatever o is. By default, it will be a logger using print statements written in stderr, but you can also provide a configured logger.