sklearn.cross_validation.check_cv(cv, X=None, y=None, classifier=False)[source]

Input checker utility for building a CV in a user friendly way.


cv : int, a cv generator instance, or None

The input specifying which cv generator to use. It can be an integer, in which case it is the number of folds in a KFold, None, in which case 3 fold is used, or another object, that will then be used as a cv generator.

X : array-like

The data the cross-val object will be applied on.

y : array-like

The target variable for a supervised learning problem.

classifier : boolean optional

Whether the task is a classification task, in which case stratified KFold will be used.


checked_cv: a cross-validation generator instance. :

The return value is guaranteed to be a cv generator instance, whatever the input type.