Python 3：「TypeError：列表索引必須是整數，而不是str」當試圖執行代碼

Question

我試圖找到如果圖中的節點之間的路由是否可能。出於某種原因，我的代碼繼續返回「TypeError：列表索引必須是整數，而不是str」。該錯誤是在線31和17，（如果len（N）== numberOfEdges（N）：）（用於nextEdge在列表[vertexIndex] :)

lists = [] 
lists.append([]) 
lists.append([]) 
lists.append([]) 
lists.append([]) 
lists.append([]) 
lists[0] = [False,True,False,False,True] 
lists[1] = [True,False,True,True,False] 
lists[2] = [False,True,False,True,True] 
lists[3] = [False,True,True,False,True] 
lists[4] = [True,False,True,True,False] 

document = "/Users/jamesball/Documents/workspace/Workspace/testExercise.txt" 

def numberOfEdges(vertexIndex): 
    totalCount = 0 #Set a counter to 0 
    for nextEdge in lists[vertexIndex]: 
     if nextEdge == True: 
       totalCount = totalCount + 1 
    return totalCount 

def pathfinder(file): 
    file_document = open(file, 'r') 
    lists2 = [] 
    with file_document as f: 
     vals = [line.strip() for line in f] 
    for value in vals: 
     lists2.append(value) 
    for n in lists2: 
     print n 
     if len(n) == numberOfEdges(n): 
      print "True" 
     else: 
      print "false" 

pathfinder(document) 

Answer 1

當你閱讀vals = [line.strip() for line in f]從文件內容，vals保存字符串的list的值。然後您將這些字符串值傳遞給numberOfEdges()函數if len(n) == numberOfEdges(n)。但是，在numberOfEdges()函數中迭代時，您可以執行for nextEdge in lists[vertexIndex]。此時，您將該字符串（從文件讀取）作爲索引傳遞給lists[vertexIndex]，但索引應始終爲int值。

在這裏提供文件的內容可能會有所幫助。如果文件中包含int值，你必須明確其類型強制轉換爲int，而assinging vals爲：

vals = [int(line.strip()) for line in f] 
# Not sure if I am right about this 

Answer 2

閱讀評論！

lists = [] 
lists.append([]) 
lists.append([]) 
lists.append([]) 
lists.append([]) 
lists.append([]) 
lists[0] = [False,True,False,False,True] 
lists[1] = [True,False,True,True,False] 
lists[2] = [False,True,False,True,True] 
lists[3] = [False,True,True,False,True] 
lists[4] = [True,False,True,True,False] 

document = "/Users/jamesball/Documents/workspace/Workspace/testExercise.txt" 

def numberOfEdges(vertexIndex): # vertexIndex is a STRING 
    totalCount = 0 #Set a counter to 0 
    for nextEdge in lists[vertexIndex]: #PROBLEM! vertexIndex is a STRING!!! 
     if nextEdge == True: 
       totalCount = totalCount + 1 
    return totalCount 

def pathfinder(file): 
    file_document = open(file, 'r') 
    lists2 = [] 
    with file_document as f: 
     vals = [line.strip() for line in f] # puts STRINGS into vals 
    for value in vals: 
     lists2.append(value) # puts vals's STRINGS into lists2 
    for n in lists2: # iterates through each STRING 
     print n 
     if len(n) == numberOfEdges(n): # feeds numberOfEdges a STRING!!! 
      print "True" 
     else: 
      print "false" 

pathfinder(document) 

按照計算機的順序執行代碼。