PredefinedSplit#

classsklearn.model_selection.PredefinedSplit(test_fold)[source]#

Predefined split cross-validator.

Provides train/test indices to split data into train/test sets using apredefined scheme specified by the user with thetest_fold parameter.

Read more in theUser Guide.

Added in version 0.16.

Parameters:

test_foldarray-like of shape (n_samples,)

The entrytest_fold[i] represents the index of the test set thatsamplei belongs to. It is possible to exclude samplei fromany test set (i.e. include samplei in every training set) bysettingtest_fold[i] equal to -1.

Examples

>>>importnumpyasnp>>>fromsklearn.model_selectionimportPredefinedSplit>>>X=np.array([[1,2],[3,4],[1,2],[3,4]])>>>y=np.array([0,0,1,1])>>>test_fold=[0,1,-1,1]>>>ps=PredefinedSplit(test_fold)>>>ps.get_n_splits()2>>>print(ps)PredefinedSplit(test_fold=array([ 0,  1, -1,  1]))>>>fori,(train_index,test_index)inenumerate(ps.split()):...print(f"Fold{i}:")...print(f"  Train: index={train_index}")...print(f"  Test:  index={test_index}")Fold 0:  Train: index=[1 2 3]  Test:  index=[0]Fold 1:  Train: index=[0 2]  Test:  index=[1 3]

get_metadata_routing()[source]#

Get metadata routing of this object.

Please checkUser Guide on how the routingmechanism works.

Returns:

routingMetadataRequest

AMetadataRequest encapsulatingrouting information.

get_n_splits(X=None,y=None,groups=None)[source]#

Returns the number of splitting iterations in the cross-validator.

Parameters:

Xobject

Always ignored, exists for compatibility.

yobject

Always ignored, exists for compatibility.

groupsobject

Always ignored, exists for compatibility.

Returns:

n_splitsint

Returns the number of splitting iterations in the cross-validator.

split(X=None,y=None,groups=None)[source]#

Generate indices to split data into training and test set.

Parameters:

Xobject

Always ignored, exists for compatibility.

yobject

Always ignored, exists for compatibility.

groupsobject

Always ignored, exists for compatibility.

Yields:

trainndarray

The training set indices for that split.

testndarray

The testing set indices for that split.