代码生成波士顿房价预测集成学习
时间: 2023-07-19 11:45:38 浏览: 55
好的,我可以给您提供一个基于集成学习的波士顿房价预测的代码示例,使用的是 Python 语言和 Scikit-learn 库。
首先,我们需要导入必要的库和读取数据集:
```python
import pandas as pd
import numpy as np
from sklearn.datasets import load_boston
from sklearn.model_selection import train_test_split
from sklearn.metrics import mean_squared_error
from sklearn.tree import DecisionTreeRegressor
from sklearn.linear_model import LinearRegression
from sklearn.ensemble import RandomForestRegressor
# 读取数据集
boston = load_boston()
X = pd.DataFrame(boston.data, columns=boston.feature_names)
y = pd.Series(boston.target)
```
接下来,我们将数据集拆分为训练集和测试集,并定义一些基本的回归模型:
```python
# 拆分数据集
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42)
# 定义基本模型
models = {
'linear_regression': LinearRegression(),
'decision_tree': DecisionTreeRegressor(),
'random_forest': RandomForestRegressor(n_estimators=100)
}
```
现在,我们将使用 K 折交叉验证方法来训练和评估每个基本模型,并计算它们的平均误差:
```python
from sklearn.model_selection import KFold
# 定义交叉验证方法
kf = KFold(n_splits=5, shuffle=True, random_state=42)
# 训练和评估每个基本模型
for name, model in models.items():
scores = []
for train_index, val_index in kf.split(X_train):
X_train_cv, X_val = X_train.iloc[train_index], X_train.iloc[val_index]
y_train_cv, y_val = y_train.iloc[train_index], y_train.iloc[val_index]
model.fit(X_train_cv, y_train_cv)
y_pred = model.predict(X_val)
scores.append(mean_squared_error(y_val, y_pred))
print(f'{name} CV MSE: {np.mean(scores):.2f} +/- {np.std(scores):.2f}')
```
最后,我们使用集成学习方法(例如,投票或平均)来组合基本模型,并评估它们在测试集上的性能:
```python
# 定义集成学习方法
from sklearn.ensemble import VotingRegressor
voting = VotingRegressor(list(models.items()))
# 训练并评估集成模型
voting.fit(X_train, y_train)
y_pred = voting.predict(X_test)
print(f'Ensemble test MSE: {mean_squared_error(y_test, y_pred):.2f}')
```
这就是一个基于集成学习的波士顿房价预测的示例代码。您可以根据需要进行修改和优化。