class TrainPre(object): def __init__(self, img_mean, img_std): self.img_mean = img_mean self.img_std = img_std def __call__(self, img, hha): img = normalize(img, self.img_mean, self.img_std) hha = normalize(hha, self.img_mean, self.img_std) p_img = img.transpose(2, 0, 1) p_hha = hha.transpose(2, 0, 1) extra_dict = {'hha_img': p_hha} return p_img, extra_dict这段代码什么意思

这段代码是一个 Python 类，名为 TrainPre，用于对输入的图像和 HHA 图像进行预处理。在初始化时，传入均值和标准差作为参数。在调用时，将输入的图像和 HHA 图像进行归一化处理，并将它们转换为 PyTorch 可以处理的格式。然后将 HHA 图像存储在字典变量 extra_dict 中，并将处理后的图像和字典变量作为结果返回。

相关问题

class PhoneDirectory: def __init__(self): self.tel_hash = {} self.name_hash = {}如何用链表表达

在Python中，`tel_hash` 和 `name_hash` 是两个字典，用于存储电话号码（键）和对应的名字（值）。如果你想使用链表来表示这些数据结构，我们需要转换为双向链表，因为字典本质上已经是哈希表，提供了非常快的查找性能。但在链表中，插入、删除操作可能会慢一些。

首先，定义一个节点类（Node）来构建链表：

class Node:
    def __init__(self, tel, name=None):
        self.tel = tel
        self.name = name
        self.prev = None
        self.next = None

class LinkedListPhoneDirectory:
    def __init__(self):
        self.head = None
        self.tail = None

    # 插入方法
    def insert(self, tel, name):
        if not self.head:
            self.head = Node(tel, name)
            self.tail = self.head
        else:
            new_node = Node(tel, name)
            self.tail.next = new_node
            new_node.prev = self.tail
            self.tail = new_node

    # 查找方法（这里只简单地遍历链表）
    def find_by_tel(self, tel):
        current = self.head
        while current and current.tel != tel:
            current = current.next
        return current

# 示例
phone_directory = LinkedListPhoneDirectory()
phone_directory.insert("123", "Alice")

在这个实现中，`LinkedListPhoneDirectory` 类有一个头节点 `head` 和尾节点 `tail`，分别代表链表的开始和结束。`insert` 方法用于在链表末尾添加新条目，`find_by_tel` 方法用于根据电话号码查找对应的节点。

优化代码class DeliveryRequest: def __init__(self, name, location, time): self.name = name self.location = location self.time = time class DeliveryStation: def __init__(self, location): self.location = location self.requests = [] def add_request(self, request): self.requests.append(request) def match_deliveryman(self, deliverymen): for request in self.requests: for deliveryman in deliverymen: if request.location == deliveryman.location and request.time == deliveryman.available_time: print(f"您有一个快递将送给{request.name}，请您按时送货") print(f"您的快递将由{deliveryman.name}在{request.time}送达，请您按时等候") deliverymen.remove(deliveryman) break class DeliveryMan: def __init__(self, name, location, available_time): self.name = name self.location = location self.available_time = available_time class Dispatcher: def __init__(self, delivery_stations, deliverymen): self.delivery_stations = delivery_stations self.deliverymen = deliverymen def dispatch(self): for station in self.delivery_stations: station.match_deliveryman(self.deliverymen)

可以考虑优化代码的可读性和效率，例如使用列表推导式和更好的命名：

class DeliveryRequest:
    def __init__(self, name, location, time):
        self.name = name
        self.location = location
        self.time = time

class DeliveryStation:
    def __init__(self, location):
        self.location = location
        self.requests = []

    def add_request(self, request):
        self.requests.append(request)

    def match_deliveryman(self, deliverymen):
        for request in self.requests:
            matching_deliverymen = [dm for dm in deliverymen if dm.location == request.location and dm.available_time == request.time]
            for deliveryman in matching_deliverymen:
                print(f"您有一个快递将送给{request.name}，请您按时送货")
                print(f"您的快递将由{deliveryman.name}在{request.time}送达，请您按时等候")
                deliverymen.remove(deliveryman)
                break

class DeliveryMan:
    def __init__(self, name, location, available_time):
        self.name = name
        self.location = location
        self.available_time = available_time

class Dispatcher:
    def __init__(self, delivery_stations, deliverymen):
        self.delivery_stations = delivery_stations
        self.deliverymen = deliverymen

    def dispatch(self):
        for station in self.delivery_stations:
            station.match_deliveryman(self.deliverymen)

这样，我们使用列表推导式来创建了一个匹配的快递员列表，然后使用一个 for 循环来遍历它。我们也使用更好的变量名来提高代码的可读性。