使用比较函数查找两个对象列表的交集

Question

tl;博士：

我在 Python 中有两个 class 对象列表（都是同一类型），在比较它们时，我需要通过使用returns True 或 False.

的函数

我需要比较汽车的轮胎以确定轮胎是否匹配（“它会适合”），有时轮胎是否相同（相同brand/make/year）。

Given the example below, how can I compare the car's current tires to a list of potential tires I got back from the previous find call using the compare.is_exact_match function?

我见过类似的问题，例如，它让我可以根据属性的值比较对象，但我不确定这种方法是否（如何）适用于功能比较。

详情：

我有一个Car，它的一个属性是一组轮胎（subclass Tire）：

def Car:
    def __init__(self, ...args):
         self.make = make
         self.model = model
         self.year = year
         self.trim = trim
         self.color = color
         self.vin = vin
         self.tires: [Tire] = tires
         self.potential_matches: [Tire] = []

    def Tire:
        def __init__(self, ...args):
            self.brand = brand
            self.model_number = model_number
            self.year = year
            self.diameter = diameter
            self.width = width
            self.sidewall = sidewall
            self.circumference = self.circumference
            self.revs_per_mile = self.revs_per_mile

我有一些比较复杂的启发式方法，可以比较汽车列表以找到与这辆车匹配的轮胎。这是一个模拟示例，但我们假设这是一个轮胎交换市场，以便您了解我们如何去那里。在这种理论产品中，市场上的轮胎数据往往是不完整的。确定轮胎是否匹配非常昂贵，因此我们做了一些准备工作以减少足迹。一旦我们有了它，我们通常需要进一步比较轮胎以区分“只是匹配”和“相同的轮胎”。

这看起来像：

@classmethod
def find(cls, car: Car, marketplace_cars: [Car]) -> [Car.Tire]:
    matches = list(filter(lambda c:
         # One thing we can try is comparing the car first. If the car is a match,
         # the tires probably are too.
         car.make == c.make
         and car.model == c.model
         and car.year == c.year
         and car.trim == c.trim

         # If any of those fail, run the expensive heuristic
         and compare.is_match(car, c)
    marketplace_cars))

    # Extract a list of tires from the list of cars that were identified as having matches
    matching_tires = list(itertools.chain(*[m.tires for m in matches]))

    return matching_tires

现在，我们希望从此列表中进一步缩小范围，以显示所有相同匹配的轮胎。这意味着在第一次比较中比较品牌、型号和里程以及所有其他内容。这次 compare.is_exact_match 获取单个 Tire 对象并比较它们。

这就是我迷路的地方：

How can I compare the car's current tires to a list of potential tires I got back from the previous find call using the compare.is_exact_match function?

@classmethod
def find_exact(cls, car: Car) -> [Car.Tire]:

    # Pseudo code, because what do I do here?
    # Should/can I do this with sets, or?
    exact_matches = list(filter(
                          lambda tire, match: compare.is_exact_match(tire, match), 
                          (car.tires, car.potential_matches)))

    # Returns an array of [Car.Tire] that are exact matches
    return exact_matches

Answer 1

事实证明我真的想多了，我只需要一个简单的列表理解。

@classmethod
def find_exact(cls, car: Car) -> [Car.Tire]:

    exact_matches = [m for t in car.tires for m in car.potential_matches if compare.is_exact_match(t, m)]
    """
    for t in car.tires:
        for m in car.potential_matches:
            if compare.is_exact_match(t, m):
                m
    """

    # Returns an array of [Car.Tire] that are exact matches
    return exact_matches

使用比较函数查找两个对象列表的交集

Find the intersection of two lists of objects by using a comparison function

python

comparison

python-3.x

tl;博士：

详情：