Question

我正试图获得一棵树的深度。以下是我的代码：

def getTreeDepth(myTree):
    maxDepth = 0
    firstStr = list(myTree.keys())[0]
    secondDict = myTree[firstStr]
    for key in list(secondDict.keys()):
        if type(secondDict[key]).__name__ == 'dict':
            thisDepth = 1+ getTreeDepth(secondDict)
        else:
            thisDepth = 1
        if thisDepth > maxDepth: maxDepth = thisDepth

    return maxDepth

然而，当我运行它时：

myTree = {'no surfacing': {0: 'no', 1: {'flippers': {0: 'no', 1: 'yes'}}}}
getTreeDepth(myTree)


<ipython-input-54-d4442919fa4f> in getTreeDepth(myTree)
     17     firstStr = list(myTree.keys())[0]
     18     secondDict = myTree[firstStr]
---> 19     for key in list(secondDict.keys()):
     20         if type(secondDict[key]).__name__ == 'dict':
     21             thisDepth = 1+ getTreeDepth(secondDict)

AttributeError: 'str' object has no attribute 'keys'

如何在不更改此算法的情况下更正它？

非常感谢！

Answer 1

myTree = {
    'no surfacing': { 
        0: 'no', 
        1: {
            'flippers': {
                0: 'no', 
                1: 'yes'}}}}

def myTreeDepth(myTree):
    maxDepth = 0
    for value in myTree.values():
        if type(value) == type({}): 
            thisDepth = 1 + myTreeDepth(value)
        else:
            thisDepth = 1
        if thisDepth > maxDepth: 
            maxDepth = thisDepth
    return maxDepth
print('maxDepth =', getTreeDepth(myTree))

给出：

maxDepth = 4

注意：

字典的.keys()方法返回一个iterable，因此不需要将返回的值转换为列表以便迭代它。这同样适用于.values()和.items()
检查字典树深度的迭代在字典.values()而非.keys()上运行。如果您想使用整个字典条目，可以使用for key, value in dict.items()
您正在使用的算法中不需要firstStr = list(myTree.keys())[0]和secondDict = myTree[firstStr]。

决策树 - 'str'对象没有属性'keys' - Python3.6

1 个答案: