决策树是一种用于分类和回归的非参数监督学习方法。目标是创建一个模型，通过从数据特性中推导出简单的决策规则来预测目标变量的值
导入类库1 import numpy as np 2 import pandas as pd 3 from sklearn.feature_extraction import DictVectorizer 4 from sklearn.tree import DecisionTreeClassifier 5 from sklearn.model_selection import train_test_split