sklearn.datasets
.make_classification¶

sklearn.datasets.
make_classification
(n_samples=100, n_features=20, n_informative=2, n_redundant=2, n_repeated=0, n_classes=2, n_clusters_per_class=2, weights=None, flip_y=0.01, class_sep=1.0, hypercube=True, shift=0.0, scale=1.0, shuffle=True, random_state=None)[source]¶ Generate a random nclass classification problem.
This initially creates clusters of points normally distributed (std=1) about vertices of an
n_informative
dimensional hypercube with sides of length2*class_sep
and assigns an equal number of clusters to each class. It introduces interdependence between these features and adds various types of further noise to the data.Without shuffling,
X
horizontally stacks features in the following order: the primaryn_informative
features, followed byn_redundant
linear combinations of the informative features, followed byn_repeated
duplicates, drawn randomly with replacement from the informative and redundant features. The remaining features are filled with random noise. Thus, without shuffling, all useful features are contained in the columnsX[:, :n_informative + n_redundant + n_repeated]
.Read more in the User Guide.
 Parameters
 n_samplesint, optional (default=100)
The number of samples.
 n_featuresint, optional (default=20)
The total number of features. These comprise
n_informative
informative features,n_redundant
redundant features,n_repeated
duplicated features andn_featuresn_informativen_redundantn_repeated
useless features drawn at random. n_informativeint, optional (default=2)
The number of informative features. Each class is composed of a number of gaussian clusters each located around the vertices of a hypercube in a subspace of dimension
n_informative
. For each cluster, informative features are drawn independently from N(0, 1) and then randomly linearly combined within each cluster in order to add covariance. The clusters are then placed on the vertices of the hypercube. n_redundantint, optional (default=2)
The number of redundant features. These features are generated as random linear combinations of the informative features.
 n_repeatedint, optional (default=0)
The number of duplicated features, drawn randomly from the informative and the redundant features.
 n_classesint, optional (default=2)
The number of classes (or labels) of the classification problem.
 n_clusters_per_classint, optional (default=2)
The number of clusters per class.
 weightsarraylike of shape (n_classes,) or (n_classes  1,), (default=None)
The proportions of samples assigned to each class. If None, then classes are balanced. Note that if
len(weights) == n_classes  1
, then the last class weight is automatically inferred. More thann_samples
samples may be returned if the sum ofweights
exceeds 1. flip_yfloat, optional (default=0.01)
The fraction of samples whose class is assigned randomly. Larger values introduce noise in the labels and make the classification task harder.
 class_sepfloat, optional (default=1.0)
The factor multiplying the hypercube size. Larger values spread out the clusters/classes and make the classification task easier.
 hypercubeboolean, optional (default=True)
If True, the clusters are put on the vertices of a hypercube. If False, the clusters are put on the vertices of a random polytope.
 shiftfloat, array of shape [n_features] or None, optional (default=0.0)
Shift features by the specified value. If None, then features are shifted by a random value drawn in [class_sep, class_sep].
 scalefloat, array of shape [n_features] or None, optional (default=1.0)
Multiply features by the specified value. If None, then features are scaled by a random value drawn in [1, 100]. Note that scaling happens after shifting.
 shuffleboolean, optional (default=True)
Shuffle the samples and the features.
 random_stateint, RandomState instance or None (default)
Determines random number generation for dataset creation. Pass an int for reproducible output across multiple function calls. See Glossary.
 Returns
 Xarray of shape [n_samples, n_features]
The generated samples.
 yarray of shape [n_samples]
The integer labels for class membership of each sample.
See also
make_blobs
simplified variant
make_multilabel_classification
unrelated generator for multilabel tasks
Notes
The algorithm is adapted from Guyon [1] and was designed to generate the “Madelon” dataset.
References
 1
I. Guyon, “Design of experiments for the NIPS 2003 variable selection benchmark”, 2003.