路徑查找器的代碼，__getitem__類型錯誤

Question

我試圖做一個「路徑查找器」

def find_all_paths(start, end, graph, path=[]): 
    path = path + [start] 
    if start == end: 
     return [path] 
    paths = [] 
    for node in graph[start]: 
     if node not in path: 
      newpaths = find_all_paths(graph, node, end, path) 
      for newpath in newpaths: 
       paths.append(newpath) 
    return paths 


graph={1: ['2'], 2: ['3', '4', '5'], 3: ['4'], 4: ['5', '6'], 5: [], 6: []} 

，如果我在shell中輸入find_all_paths(2,5,graph)我應該找回所有從鍵2走在圖形詞典的路徑在5個值 正確的結果應該是這樣的

path=[[2,5],[2,3,4,5][2,4,5]] 

代碼一直給值錯誤，如

for node in graph[start]: 
TypeError: 'int' object has no attribute '__getitem__' 

可能有人請幫助我得到這個東西運行

Answer 1

有一些尷尬和錯誤：

而是與列表初始化的路徑參數，使用None。 並在函數體中創建空列表。

def find_all_paths(start, end, graph, path=None): 
    path = path or [] 

傳遞給find_all_paths的值不考慮簽名。代替 寫：

newpaths = find_all_paths(node, end, graph, path) 

由於值是整數，該圖形必須包含int代替strings。

graph = {1: [2], 2: [3, 4, 5], 3: [4], 4: [5, 6], 5: [], 6: []} 

這裏是你的代碼的固定版本：

def find_all_paths(start, end, graph, path=None): 
    path = path or [] 
    path.append(start) 
    if start == end: 
     return [path] 
    paths = [] 
    for node in graph[start]: 
     if node not in path: 
      newpaths = find_all_paths(node, end, graph, path) 
      for newpath in newpaths: 
       paths.append(newpath) 
    return paths 

如果你試試這個：

graph = {1: [2], 2: [3, 4, 5], 3: [4], 4: [5, 6], 5: [], 6: []} 
print(find_all_paths(2, 5, graph)) 

您將獲得：

[[2, 3, 4, 5, 6]]