決策樹ID3算法

TypeError: 'dict_keys' object does not support indexing

來源：python常見錯誤集合

9.TypeError: ‘dict_keys’ object does not support indexing

這個問題是python版本的問題

#如果使用的是python2
firstStr = myTree.keys()[0]
#LZ使用的是python3
firstSides = list(myTree.keys())
firstStr = firstSides[0]12345

這是看決策樹代碼出現的問題，python3如果運行

firstStr = myTree.keys()[0]1

就會報這個錯誤，解決辦法就是先轉換成list，再把需要的索引提取出來。

NameError: name 'trainLabel' is not defined

    def labelCount(self, dataset):
        labelCount = {}
        for i in dataset:
            if trainLabel[i] in labelCount.keys():
                labelCount[trainLabel[i]] += 1
            else:
                labelCount[trainLabel[i]] = 1

        return labelCount

# 改爲
    def labelCount(self, dataset):
        labelCount = {}
        for i in dataset:
            if self.trainLabel[i] in labelCount.keys():
                labelCount[self.trainLabel[i]] += 1
            else:
                labelCount[self.trainLabel[i]] = 1

        return labelCount