Paired sotring

README.md

Paired sotring

paired_sorting.py

from random import randint


class Foo:
    def __init__(self, attr, x):
        self.attr = attr
        self.x = x

    def __eq__(self, other):
        if isinstance(other, Foo):
            return self.attr == other.attr

    def __repr__(self):
        return "F(a=%02d)" % self.attr


class NoVel:
    def __repr__(self):
        return "_(    )"


none = NoVel()


def generator(count):
    for attr in range(count):
        r = randint(0, 3)
        if r == 0:
            yield Foo(attr, True)
            yield None
        if r == 1:
            yield None
            yield Foo(attr, False)
        if r >= 2:
            yield Foo(attr, True)
            yield Foo(attr, False)


revs = [f for f in generator(20) if f is not None]

sorted_revs = sorted(
    revs, key=lambda r: (r.attr, -r.x)
)
paired_revs = {"L": [], "R": []}
for i, rev in enumerate(sorted_revs):
    if rev.x:
        paired_revs["R"].append(rev)
        paired_revs["L"].append(none)
    else:
        if paired_revs["R"] and paired_revs["R"][-1] == rev:
            paired_revs["L"][-1] = rev
        else:
            paired_revs["R"].append(none)
            paired_revs["L"].append(rev)

print(paired_revs["R"])
print(paired_revs["L"])