`sklearn.feature_selection`.SelectKBest¶

class sklearn.feature_selection.SelectKBest(score_func=<function f_classif at 0x2b9c8bc98488>, k=10)¶

Select features according to the k highest scores.

Parameters:

score_func : callable

Function taking two arrays X and y, and returning a pair of arrays (scores, pvalues).

k : int or “all”, optional, default=10

Number of top features to select. The “all” option bypasses selection, for use in a parameter search.

Attributes:

`scores_` : array-like, shape=(n_features,)

Scores of features.

`pvalues_` : array-like, shape=(n_features,)

p-values of feature scores.

Notes

Ties between features with equal scores will be broken in an unspecified way.

Methods

`fit`(X, y)	Run score function on (X, y) and get the appropriate features.
`fit_transform`(X[, y])	Fit to data, then transform it.
`get_params`([deep])	Get parameters for this estimator.
`get_support`([indices])	Get a mask, or integer index, of the features selected
`inverse_transform`(X)	Reverse the transformation operation
`set_params`(**params)	Set the parameters of this estimator.
`transform`(X)	Reduce X to the selected features.

__init__(score_func=<function f_classif at 0x2b9c8bc98488>, k=10)¶

fit(X, y)¶

Run score function on (X, y) and get the appropriate features.

Parameters:

X : array-like, shape = [n_samples, n_features]

The training input samples.

y : array-like, shape = [n_samples]

The target values (class labels in classification, real numbers in regression).

Returns:

self : object

Returns self.

fit_transform(X, y=None, **fit_params)¶

Fit to data, then transform it.

Fits transformer to X and y with optional parameters fit_params and returns a transformed version of X.

Parameters:

X : numpy array of shape [n_samples, n_features]

Training set.

y : numpy array of shape [n_samples]

Target values.

Returns:

X_new : numpy array of shape [n_samples, n_features_new]

Transformed array.

get_params(deep=True)¶

Get parameters for this estimator.

Parameters:

deep: boolean, optional :

If True, will return the parameters for this estimator and contained subobjects that are estimators.

Returns:

params : mapping of string to any

Parameter names mapped to their values.

get_support(indices=False)¶

Get a mask, or integer index, of the features selected

Parameters:

indices : boolean (default False)

If True, the return value will be an array of integers, rather than a boolean mask.

Returns:

support : array

An index that selects the retained features from a feature vector. If indices is False, this is a boolean array of shape [# input features], in which an element is True iff its corresponding feature is selected for retention. If indices is True, this is an integer array of shape [# output features] whose values are indices into the input feature vector.

inverse_transform(X)¶

Reverse the transformation operation

Parameters:

X : array of shape [n_samples, n_selected_features]

The input samples.

Returns:

X_r : array of shape [n_samples, n_original_features]

X with columns of zeros inserted where features would have been removed by transform.

set_params(**params)¶

Set the parameters of this estimator.

The method works on simple estimators as well as on nested objects (such as pipelines). The former have parameters of the form <component>__<parameter> so that it’s possible to update each component of a nested object.