filterutil 1.0.3

Let you register and use filters in right way

filterutil

filterutil is simple, yet very powerful filtering tool.

How to install

You could install from PyPi:

$ python3 -m pip install filterutil

How to use

Simple filter

from filterutil import Filter


def test_func():
    my_filter = Filter(lambda x: x == 1)
    # assert False
    assert not my_filter.apply(2):

Filter with saved args and kwargs

from typing import Set
from filterutil import Filter


def filtering_func(value: int, y: int):
    return value == y


def test_func():
    # saved args works
    my_filter = Filter(filtering_func, 1)
    # but we recommend to use kwargs
    my_filter = Filter(filtering_func, y=1)

    # assert False
    assert not my_filter.apply(2):
    # .apply under the hood works as
    assert not filtering_func(2, y=1)

    # assert True
    assert my_filter.apply(1):

Coupling filters with AND policy

from filterutil import Filter


def test_func():
    a = Filter(lambda x: x == 1)
    b = Filter(lambda x: isinstance(x, int))
    compound_filter = a & b
    # order matters:
    #     "compound_filter = a & b" means first a then b
    #     "compound_filter = b & a" means first b then a
    
    # assert False
    assert not compound_filter.apply(2)

Coupling filters with OR policy

from filterutil import Filter


def test_func():
    a = Filter(lambda x: x == 1)
    b = Filter(lambda x: isinstance(x, int))
    # order still matters
    compound_filter = a | b

    # assert True
    assert compound_filter.apply(2)

Coupling filters with XOR policy

from filterutil import Filter


def test_func():
    a = Filter(lambda x: x == 1)
    b = Filter(lambda x: x == 3)
    compound_filter = a ^ b

    # assert True
    assert compound_filter.apply(2)

Infinite nesting

from filterutil import Filter


def test_func():
    a = Filter(lambda x: isinstance(x, int))
    b = Filter(lambda x: isinstance(x, str))
    c = Filter(lambda x: x == 1)
    # multiline
    compound_filter = a | b
    compound_filter = compound_filter & c
    # order is: (a or b) and c
    # assert False
    assert not compound_filter.apply(2)

    # is not the same as inline
    # because of python operator precedence
    compound_filter = filter_a | filter_b & filter_c
    # order is: a or (b and c)
    # assert True
    assert compound_filter.apply(2)

Collection of filters with same policy

from filterutil import Filter, Filters, OrFilters, XorFilters, FilterCouplingPolicy


def test_func():
    # Filters is AND collection by default
    and_filters = Filters()
    and_filters['a'] = Filter(lambda x: isinstance(x, int))
    and_filters['b'] = Filter(lambda x: isinstance(x, str))
    
    # same as
    and_filters = Filters(
        a=Filter(lambda x: isinstance(x, int)),
        b=Filter(lambda x: isinstance(x, str)),
    )
    # ---

    # assert False
    assert not and_filters.apply(2)

    # OR collection
    or_filters = OrFilters()
    
    #same as 
    or_filters = Filters(FilterCouplingPolicy.OR)
    # ---

    or_filters['a'] = Filter(lambda x: isinstance(x, int))
    or_filters['b'] = Filter(lambda x: isinstance(x, str))

    # assert True
    assert or_filters.apply(2)
    
    # XOR collection
    xor_filters = XorFilters()

    #same as 
    xor_filters = Filters(FilterCouplingPolicy.XOR)
    # ---

    xor_filters['a'] = Filter(lambda x: isinstance(x, int))
    xor_filters['b'] = Filter(lambda x: isinstance(x, str))

    # assert True
    assert xor_filters.apply(False)

It is possible to select certain filters of collection

from filterutil import Filter, Filters, OrFilters


def test_func():
    and_filters = Filters(
        a=Filter(lambda x: x == 2), 
        b=Filter(lambda x: isinstance(x, int)),
        c=Filter(lambda x: isinstance(x, str)),
    )
    assert and_filters.apply(2, filter_names=['a', 'b'])
    assert not and_filters.apply(2, filter_names=['b', 'c'])

    or_filters = OrFilters(
        a=Filter(lambda x: x == 1), 
        b=Filter(lambda x: isinstance(x, int)),
        c=Filter(lambda x: isinstance(x, str)),
    )
    assert or_filters.apply(2, filter_names=['a', 'b'])
    assert not or_filters.apply(2, filter_names=['a', 'c'])

Apply another coupling policy for the collection dinamically

from filterutil import Filter, Filters, OrFilters, FilterCouplingPolicy


def test_func():
    and_filters = Filters(
        a=Filter(lambda x: x == 1), 
        b=Filter(lambda x: isinstance(x, int)),
    )
    assert not and_filters.apply(2)
    assert and_filters.apply_or(2)
    # or
    assert and_filters.apply(2, coupling_policy=FilterCouplingPolicy.OR)


    or_filters = OrFilters(
        a=Filter(lambda x: x == 1), 
        b=Filter(lambda x: isinstance(x, int)),
    )
    assert or_filters.apply(2)
    assert not or_filters.apply_and(2)
    assert not or_filters.apply_xor(2)

Infinite nesting of collections

from filterutil import Filter, Filters, OrFilters, XorFilters, FilterCouplingPolicy


def test_func():
    and_filters = Filters(
        FilterCouplingPolicy.AND,
        a=Filter(lambda x: isinstance(x, int)),
        b=Filter(lambda x: isinstance(x, str)),
    )
    xor_filters = Filters(
        FilterCouplingPolicy.XOR,
        a=Filter(lambda x: x == 1),
        b=Filter(lambda x: x == 3),
    )

    two_collections_in_one = OrFilters(
        first=and_filters,
        second=xor_filters,
    )
    # assert True
    assert two_collections_in_one.apply(2)