更新时间:2023-12-02 11:57:40
You can use sklearn's StratifiedKFold
, from the online docs:
分层的K-folds交叉验证迭代器
Stratified K-Folds cross validation iterator
提供培训/测试 用于在火车测试集中拆分数据的索引.
Provides train/test indices to split data in train test sets.
此交叉验证对象 是KFold的变体,它返回分层的折叠.褶皱是 通过保留每个类别的样本百分比来制作.
This cross-validation object is a variation of KFold that returns stratified folds. The folds are made by preserving the percentage of samples for each class.
>>> from sklearn import cross_validation
>>> X = np.array([[1, 2], [3, 4], [1, 2], [3, 4]])
>>> y = np.array([0, 0, 1, 1])
>>> skf = cross_validation.StratifiedKFold(y, n_folds=2)
>>> len(skf)
2
>>> print(skf)
sklearn.cross_validation.StratifiedKFold(labels=[0 0 1 1], n_folds=2,
shuffle=False, random_state=None)
>>> for train_index, test_index in skf:
... print("TRAIN:", train_index, "TEST:", test_index)
... X_train, X_test = X[train_index], X[test_index]
... y_train, y_test = y[train_index], y[test_index]
TRAIN: [1 3] TEST: [0 2]
TRAIN: [0 2] TEST: [1 3]
这将保留您的类别比率,以便拆分保留类别比率,这对pandas dfs可以很好地工作.
This will preserve your class ratios so that the splits retain the class ratios, this will work fine with pandas dfs.
按照@Ali_m的建议,您可以使用 StratifiedShuffledSplit
接受拆分比率参数:
As suggested by @Ali_m you could use StratifiedShuffledSplit
which accepts a split ratio param:
sss = StratifiedShuffleSplit(y, 3, test_size=0.7, random_state=0)
将产生70%的拆分.