>>> from sklearn.datasets import load_iris

>>> from sklearn.feature_selection import SelectKBest

>>> from sklearn.feature_selection import chi2

>>> X, y = load_iris(return_X_y=True)

>>> X.shape

(150, 4)

>>> X_new = SelectKBest(chi2, k=2).fit_transform(X, y)

>>> X_new.shape

(150, 2)

from sklearn.feature_selection import VarianceThreshold

sel = VarianceThreshold(threshold=(0.95 * (1 - 0.95)))

sel_=sel.fit_transform(features)