from sklearn.tree import DecisionTreeClassifier
from sklearn.datasets import load_iris
import matplotlib.pyplot as plt
# 加載數(shù)據(jù)集
data = load_iris()
X = data.data
y = data.target
# 構建決策樹模型
model = DecisionTreeClassifier()
model.fit(X, y)
# 獲取特征重要性
importance = model.feature_importances_
# 特征重要性可視化
plt.barh(range(X.shape[1]), importance, align='center')
plt.yticks(range(X.shape[1]), data.feature_names)
plt.xlabel('Feature Importance')
plt.ylabel('Features')
plt.show()

from sklearn.ensemble import RandomForestClassifier
# 構建Random Forest模型
rf_model = RandomForestClassifier()
rf_model.fit(X, y)
# 獲取特征重要性
importance_rf = rf_model.feature_importances_
# 可視化Random Forest的特征重要性
plt.barh(range(X.shape[1]), importance_rf, align='center')
plt.yticks(range(X.shape[1]), data.feature_names)
plt.xlabel('Feature Importance')
plt.ylabel('Features')
plt.show()

import pandas as pd
# 創(chuàng)建DataFrame
df = pd.DataFrame(data.data, columns=data.feature_names)
df['target'] = data.target
# 計算Pearson相關系數(shù)
correlation = df.corr()
# 可視化相關系數(shù)矩陣
import seaborn as sns
plt.figure(figsize=(10, 8))
sns.heatmap(correlation, annot=True, cmap='coolwarm')
plt.title('Pearson Correlation Matrix')
plt.show()

from sklearn.feature_selection import mutual_info_classif

# 計算互信息
mi = mutual_info_classif(X, y)

# 可視化互信息
plt.barh(range(X.shape[1]), mi, align='center')
plt.yticks(range(X.shape[1]), data.feature_names)
plt.xlabel('Mutual Information')
plt.ylabel('Features')
plt.show()

import shap

# 創(chuàng)建并訓練一個模型（例如XGBoost）
model = xgb.XGBClassifier()
model.fit(X, y)

# 創(chuàng)建一個SHAP解釋器
explainer = shap.Explainer(model)
shap_values = explainer.shap_values(X)

# 可視化SHAP值
shap.summary_plot(shap_values, X, feature_names=data.feature_names, plot_type="bar")

from sklearn.inspection import permutation_importance

# 計算Permutation Feature Importance
result = permutation_importance(model, X, y, n_repeats=10, random_state=42)

# 可視化Permutation Feature Importance
sorted_idx = result.importances_mean.argsort()
plt.barh(range(X.shape[1]), result.importances_mean[sorted_idx], align='center')
plt.yticks(range(X.shape[1]), data.feature_names[sorted_idx])
plt.xlabel('Permutation Importance')
plt.ylabel('Features')
plt.show()

from sklearn.ensemble import GradientBoostingClassifier

# 構建GBDT模型
gbdt_model = GradientBoostingClassifier()
gbdt_model.fit(X, y)

# 獲取特征重要性
importance_gbdt = gbdt_model.feature_importances_

# 可視化GBDT的特征重要性
plt.barh(range(X.shape[1]), importance_gbdt, align='center')
plt.yticks(range(X.shape[1]), data.feature_names)
plt.xlabel('Feature Importance')
plt.ylabel('Features')
plt.show()

import xgboost as xgb
# 轉換數(shù)據(jù)為DMatrix格式
dtrain = xgb.DMatrix(X, label=y)
# 定義參數(shù)
param = {'objective': 'multi:softmax', 'num_class': 3}
# 訓練模型
num_round = 10
xgb_model = xgb.train(param, dtrain, num_round)
# 可視化特征重要性
xgb.plot_importance(xgb_model)
plt.show()