本地验证

用 Python 赢下 Kaggle 竞赛

Yauhen Babakhin

Kaggle Grandmaster

动机

过拟合示例：公共与私有排行榜

留出集

留出集示意图

留出集

留出集示意图

留出集

留出集示意图

K 折交叉验证

将训练集分成四折

K 折交叉验证

K 折交叉验证示意图

K 折交叉验证

# Import KFold
from sklearn.model_selection import KFold

# Create a KFold object
kf = KFold(n_splits=5, shuffle=True, random_state=123)

# Loop through each cross-validation split
for train_index, test_index in kf.split(train):

    # Get training and testing data for the corresponding split
    cv_train, cv_test = train.iloc[train_index], train.iloc[test_index]

分层 K 折

分层 K 折交叉验证示意图

分层 K 折

# Import StratifiedKFold
from sklearn.model_selection import StratifiedKFold


# Create a StratifiedKFold object
str_kf = StratifiedKFold(n_splits=5, shuffle=True, random_state=123)


# Loop through each cross-validation split
for train_index, test_index in str_kf.split(train, train['target']):
    cv_train, cv_test = train.iloc[train_index], train.iloc[test_index]

Passons à la pratique !

用 Python 赢下 Kaggle 竞赛