编写决策树的Python代码

决策树可以使用Python的机器学习库scikit-learn进行编写。以下是一个简单的决策树示例代码：

import numpy as np
import pandas as pd
from sklearn.tree import DecisionTreeClassifier
from sklearn.model_selection import train_test_split

# 加载数据
data = pd.read_csv("data.csv")

# 划分数据集
X = data.iloc[:, :-1]
y = data.iloc[:, -1]
X_tra