base.py 文件源码

def transform(self, X, mask=None):
        """Reduce X to the selected features.
        Parameters
        ----------
        X : array of shape [n_samples, n_features]
            The input samples.
        Returns
        -------
        X_r : array of shape [n_samples, n_selected_features]
            The input samples with only the selected features.
        """

        X = check_array(X, accept_sparse='csr')

        if mask is None:
            mask = self.get_support()

        if not mask.any():
            warn("No features were selected: either the data is"
                 " too noisy or the selection test too strict.",
                 UserWarning)
            return np.empty(0).reshape((X.shape[0], 0))

        if len(mask) != X.shape[1]:
            raise ValueError("X has a different shape than during fitting.")

        return X[:, self.safe_mask(X, mask)]