Appending a self constructed class in priority que gives TypeError: '<' not supported between instances of 'str' and 'Node'

Question

import sys
from queue import PriorityQueue

class Node(object):
    def __init__(self, data = None):
        self.value = data
        self.right = None
        self.left = None

class Huffman():
    def __init__(self, data):
        self.data = data
    
    def encoding(self):
        my_dict = {}
        for i in self.data:
            my_dict[i] = my_dict.get(i, 0)+1
        q = PriorityQueue()
        for i, j in my_dict.items():
            q.put((j,i))
        while q.qsize() >= 2:
            val_1 = q.get()
            val_2 = q.get()
            new_node_1 = Node(val_1[0]+val_2[0])
            if isinstance(val_1[1], str):
                new_node_1.left = val_1[1]
            else:
                new_node_1.left = val_1[1]
            if isinstance(val_2[1], str):
                new_node_1.right = val_2[1]
            else:
                new_node_1.right = val_2[1]
            q.put((new_node_1.value, new_node_1))

在这里，我在while循环中遇到错误，经过几次操作后它无法使用方法q.get()，或q.put()。例如，Huffman('AADCIDCVUSHDUSHUSAHDIADHIAD').encoding() 我不想更改整个代码，而只是想更改优先级，以便它仅根据第一个元素（整数）对条目进行优先级排序。

Answer 1

你是对的，优先级队列不知道如何比较 str 和节点。您必须覆盖节点中的比较器函数 class 让优先级队列知道如何比较两种不同的类型。

示例（根据需要更改比较器）：

class Node(object):
    def __init__(self, data=None):
        self.value = data
        self.right = None
        self.left = None

    def __lt__(self, obj):
        """self < obj."""
        return self.value < obj

    def __le__(self, obj):
        """self <= obj."""
        return self.value <= obj

    def __eq__(self, obj):
        """self == obj."""
        return self.value == obj

    def __ne__(self, obj):
        """self != obj."""
        return self.value != obj

    def __gt__(self, obj):
        """self > obj."""
        return self.value > obj

    def __ge__(self, obj):
        """self >= obj."""
        return self.value >= obj

Appending a self constructed class in priority que gives TypeError: '<' not supported between instances of 'str' and 'Node'

Appending a self constructed class in priority que gives TypeError: '<' not supported between instances of 'str' and 'Node'

python

class

priority-queue

typeerror

huffman-code