【内含baseline】Kaggle机器学习新赛指南!文末送书~

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日前,Kaggle发布了ICR - Identifying Age-Related Conditions疾病识别大赛。这是一个机器学习中的二分类任务,需要你使用ML的方法对病人进行诊断,判断病人是否有相关疾病,从而为医生提供进行合理诊断的依据。

本次比赛提供了4份数据,分别是:

train、test、sample_submission、greeks。其中:

train文件标记了每个病人的相关特征和label。

test、sample_submission为提交答案时用。

greeks是补充元数据,仅适用于训练集。

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赛题讲座

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训练数据分析

Number of rows in train data: 617
Number of columns data: 58

数据样例:

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数据分布:

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相关性分析:

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构建训练数据

读取数据,具体可以详见baseline代码,里面有更为详细的介绍

train             = pd.read_csv('/kaggle/input/icr-identify-age-related-conditions/train.csv')
test              = pd.read_csv('/kaggle/input/icr-identify-age-related-conditions/test.csv')
greeks            = pd.read_csv('/kaggle/input/icr-identify-age-related-conditions/greeks.csv')
sample_submission = pd.read_csv('/kaggle/input/icr-identify-age-related-conditions/sample_submission.csv')

Baseline流程

加载数据,特征处理:

from sklearn.impute import SimpleImputer
from sklearn.preprocessing import MinMaxScaler, OneHotEncoder


# Combine numeric and categorical features
FEATURES = num_cols + cat_cols


# Fill missing values with mean for numeric variables
imputer = SimpleImputer(strategy='mean')
numeric_df = pd.DataFrame(imputer.fit_transform(train[num_cols]), columns=num_cols)


# Scale numeric variables using min-max scaling
scaler = MinMaxScaler()
scaled_numeric_df = pd.DataFrame(scaler.fit_transform(numeric_df), columns=num_cols)


# Encode categorical variables using one-hot encoding
encoder = OneHotEncoder(sparse=False, handle_unknown='ignore')
encoded_cat_df = pd.DataFrame(encoder.fit_transform(train[cat_cols]), columns=encoder.get_feature_names_out(cat_cols))


# Concatenate the scaled numeric and encoded categorical variables
processed_df = pd.concat([scaled_numeric_df, encoded_cat_df], axis=1)

定义训练函数:

from sklearn.utils import class_weight


FOLDS = 10
SEED = 1004
xgb_models = []
xgb_oof = []
f_imp = []


counter = 1
X = processed_df
y = train['Class']


# Calculate the sample weights
weights = class_weight.compute_sample_weight('balanced', y)


skf = StratifiedKFold(n_splits=FOLDS, shuffle=True, random_state=SEED)
for fold, (train_idx, val_idx) in enumerate(skf.split(X, y)):
    if (fold + 1)%5 == 0 or (fold + 1) == 1:
        print(f'{"#"*24} Training FOLD {fold+1} {"#"*24}')
        
    X_train, y_train = X.iloc[train_idx], y.iloc[train_idx]  
    X_valid, y_valid = X.iloc[val_idx], y.iloc[val_idx]
    watchlist = [(X_train, y_train), (X_valid, y_valid)]
    
    # Apply weights in the XGBClassifier
    model = XGBClassifier(n_estimators=1000, n_jobs=-1, max_depth=4, eta=0.2, colsample_bytree=0.67)
    model.fit(X_train, y_train, sample_weight=weights[train_idx], eval_set=watchlist, early_stopping_rounds=300, verbose=0)
    
    val_preds = model.predict_proba(X_valid)[:, 1]
    
    # Apply weights in the log_loss
    val_score = log_loss(y_valid, val_preds, sample_weight=weights[val_idx])
    best_iter = model.best_iteration
    
    idx_pred_target = np.vstack([val_idx,  val_preds, y_valid]).T
    f_imp.append({i: j for i, j in zip(X.columns, model.feature_importances_)})
    print(f'{" "*20} Log-loss: {val_score:.5f} {" "*6} best iteration: {best_iter}')          
    
    xgb_oof.append(idx_pred_target)   
    xgb_models.append(model)  
    
print('*'*45)
print(f'Mean Log-loss: {np.mean([log_loss(item[:, 2], item[:, 1], sample_weight=weights[item[:, 0].astype(int)]) for item in xgb_oof]):.5f}')

特征重要性查看:

# Confusion Matrix for the last fold
cm = confusion_matrix(y_valid, model.predict(X_valid))


# Feature Importance for the last model
feature_imp = pd.DataFrame({'Value':xgb_models[-1].feature_importances_, 'Feature':X.columns})
feature_imp = feature_imp.sort_values(by="Value", ascending=False)
feature_imp_top20 = feature_imp.iloc[:20]


fig, ax = plt.subplots(1, 2, figsize=(14, 4))


# Subplot 1: Confusion Matrix
sns.heatmap(cm, annot=True, fmt='d', ax=ax[0], cmap='YlOrRd')
ax[0].set_title('Confusion Matrix')
ax[0].set_xlabel('Predicted')
ax[0].set_ylabel('True')


# Subplot 2: Feature Importance
sns.barplot(x="Value", y="Feature", data=feature_imp_top20, ax=ax[1], palette='YlOrRd_r')
ax[1].set_title('Feature Importance')


plt.tight_layout()
plt.show()

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转载自blog.csdn.net/lgzlgz3102/article/details/131672064