python代码:基因型数据集CSV文件,83列,具体1个标签值,82个特征,第一行为特征名称;基于随机森林模型进行嵌入式特征选择,遴选出候选特征,输出结果为CSV文件;使用GridSearchCV进行随机森林模型调参;输出排名前50的特征为 CSV文件;绘制学习曲线以表示随机森林分类模型使用不同特征数量时的十折交叉验证分类正确率;
时间: 2024-04-16 13:25:05 浏览: 99
以下是符合你需求的Python代码示例:
```python
import pandas as pd
import numpy as np
from sklearn.ensemble import RandomForestClassifier
from sklearn.model_selection import train_test_split, GridSearchCV, cross_val_score
from sklearn.feature_selection import SelectFromModel
from sklearn.metrics import accuracy_score
import matplotlib.pyplot as plt
# 1. 加载数据集
data = pd.read_csv('genotype_dataset.csv')
X = data.iloc[:, 1:] # 特征
y = data.iloc[:, 0] # 标签
# 2. 数据预处理(如果有需要)
# 3. 特征选择
rf = RandomForestClassifier(n_estimators=100, random_state=42)
rf.fit(X, y)
feature_importances = rf.feature_importances_
selector = SelectFromModel(rf, threshold='median', prefit=True)
X_selected = selector.transform(X)
selected_features = X.columns[selector.get_support()]
# 4. 输出结果为CSV文件(候选特征)
selected_data = pd.concat([y, pd.DataFrame(X_selected, columns=selected_features)], axis=1)
selected_data.to_csv('selected_features.csv', index=False)
# 5. 随机森林模型调参
param_grid = {
'n_estimators': [100, 200, 300],
'max_depth': [None, 5, 10],
'min_samples_split': [2, 5, 10]
}
grid_search = GridSearchCV(rf, param_grid, cv=5)
grid_search.fit(X_selected, y)
best_params = grid_search.best_params_
# 6. 输出排名前50的特征为CSV文件
feature_importances_df = pd.DataFrame({'Feature': selected_features, 'Importance': feature_importances})
top_50_features = feature_importances_df.nlargest(50, 'Importance')
top_50_features.to_csv('top_50_features.csv', index=False)
# 7. 绘制学习曲线
feature_counts = range(1, len(selected_features) + 1)
cv_scores = []
for num_features in feature_counts:
X_subset = selected_data.iloc[:, 1:num_features+1]
scores = cross_val_score(rf, X_subset, y, cv=10)
cv_scores.append(scores.mean())
plt.plot(feature_counts, cv_scores)
plt.xlabel('Number of Features')
plt.ylabel('Cross-validated Accuracy')
plt.title('Learning Curve')
plt.show()
```
请注意,以上代码仅提供了一个大致的框架,你需要根据实际情况进行适当的调整和修改,比如根据你的数据集的具体位置和特征名称进行索引、对数据进行预处理等。另外,需要确保已安装所需的Python库(如pandas、numpy、sklearn和matplotlib)。
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