如何找到从给定节点到 python 中所有叶节点的路径

How to find path from a given node to all leaf nodes in python

我有一个字典,其中包含与每个节点关联的父节点和子节点列表(代码中的字典引用)。我将输入一个键(对于以下代码 B 是键)。我必须考虑父节点。对于 B 我想要的路径为 [B,C,C1,X],[B,C,C2],[B,D,D1],[B,D,D2]

我获得的以下代码的输出是:

C ['C1', 'C2']

C1 ['X']

我也收到以下错误:

File "", line 7, in path_find if d[i]['parent'] == [key]:

KeyError: 'X'

def path_find(graph,key):

    x = d[key]['child'] 
    for i in x:
        if d[i]['parent'] == [key]:
            print(i,d[i]['child'])
            path_find(d,i)


d = {'B':{
 'parent' : ['A'],
  'child': ['C','D']},
'C':{
'parent' : ['B'],
'child' : ['C1','C2']},
        'D':{
 'parent' : ['B'],
  'child': ['D1','D2']},
    'C1':{
            'parent' : ['C'],
            'child': ['X']}}

key = 'B'
path_find(d,key)

预期输出为:[B, C, C1, X], [B, C, C2], [B, D, D1], [B, D, D2]

实际输出是:

C ['C1', 'C2']

C1 ['X']

您的代码中有一些错误:

1) 您没有在 d = { ... } 中添加关于 X 节点的信息,这就是为什么您得到了 KeyError。我想这是一个没有 children.

的节点

2) 您没有保存当前节点的路径,因此您的输出无效。

更正后的代码(加上我的评论):

def path_find(graph, key, current_path, paths_list):  # graph, current node key, path to current node, all paths list
    if key not in d: # not in graph - no children
        paths_list.append(current_path)
        return
    children = d[key]['child'] 
    for child in children:  # check all children
        path_find(graph, child, current_path[:] + [child], paths_list)
    if not children:  # no children - finish search
        paths_list.append(current_path)


d = {'B':{
 'parent' : ['A'],
  'child': ['C','D']},
'C':{
'parent' : ['B'],
'child' : ['C1','C2']},
        'D':{
 'parent' : ['B'],
  'child': ['D1','D2']},
    'C1':{
            'parent' : ['C'],
            'child': ['X']}}

key = 'B'
paths_list = []
path_find(d, key, [key], paths_list)
print(paths_list)

输出:

[['B', 'C', 'C1', 'X'], ['B', 'C', 'C2'], ['B', 'D', 'D1'], ['B', 'D', 'D2']]