python – 如何更正错误’AttributeError：’dict_keys’对象没有属性’remove”？

我正在尝试使用dijkstra算法进行最短路径查找,但似乎无法正常工作.无法弄清问题是什么.这是代码和错误消息.
(我正在研究Python 3.5.https://www.youtube.com/watch?v=LHCVNtxb4ss)

graph = {
    'A': {'B': 10, 'D': 4, 'F': 10},
    'B': {'E': 5, 'J': 10, 'I': 17},
    'C': {'A': 4, 'D': 10, 'E': 16},
    'D': {'F': 12, 'G': 21},
    'E': {'G': 4},
    'F': {'E': 3},
    'G': {'J': 3},
    'H': {'G': 3, 'J': 3},
    'I': {},
    'J': {'I': 8},
}

def dijkstra(graph, start, end):
    D = {}
    P = {}
    for node in graph.keys():
        D[node]= -1
        P[node]=""
    D[start]=0
    unseen_nodes=graph.keys()
    while len(unseen_nodes) > 0:
        shortest=None
        node=' '
        for temp_node in unseen_nodes:
            if shortest==None:
                shortest = D[temp_node]
                node = temp_node
            elif D[temp_node]<shortest:
                    shortest=D[temp_node]
                    node=temp_node
        unseen_nodes.remove(node)
        for child_node, child_value in graph[node].items():
            if D[child_node] < D[node] + child_value:
                D[child_node] = D[node] + child_value
                P[child_node]=node
    path = []
    node = end
    while not (node==start):
        if path.count(node)==0:
            path.insert(0, node)
            node=P[node]
        else:
            break
    path.insert(0, start)
    return path

AttributeError：’dict_keys’对象没有属性’remove’

解决方法:

在Python 3中,dict.keys()返回a dict_keys object (a view of the dictionary),它没有删除方法;与Python 2不同,dict.keys()返回一个列表对象.

>>> graph = {'a': []}
>>> keys = graph.keys()
>>> keys
dict_keys(['a'])
>>> keys.remove('a')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'dict_keys' object has no attribute 'remove'

您可以使用list(..)来获取密钥列表：

>>> keys = list(graph)
>>> keys
['a']
>>> keys.remove('a')
>>> keys
[]

unseen_nodes = graph.keys()

至

unseen_nodes = list(graph)

标签：python-3-5,python,python-3-x,dictionary,graph-algorithm
来源： https://codeday.me/bug/20191006/1861060.html