Struct SelectKBest 

pub struct SelectKBest<F> { /* private fields */ }

An unfitted K-best feature selector.

Requires class labels (Array1<usize>) at fit time to compute per-feature ANOVA F-scores. The top K features (by score) are retained.

Examples

use ferrolearn_preprocess::feature_selection::{SelectKBest, ScoreFunc};
use ferrolearn_core::traits::{Fit, Transform};
use ndarray::{array, Array1};

let sel = SelectKBest::<f64>::new(1, ScoreFunc::FClassif);
let x = array![[1.0, 10.0], [1.0, 20.0], [2.0, 10.0], [2.0, 20.0]];
let y: Array1<usize> = array![0, 0, 1, 1];
let fitted = sel.fit(&x, &y).unwrap();
let out = fitted.transform(&x).unwrap();
assert_eq!(out.ncols(), 1);

Implementations

impl<F: Float + Send + Sync + 'static> SelectKBest<F>

pub fn new(k: usize, score_func: ScoreFunc) -> Self

Create a new SelectKBest selector.

Parameters

• k — the number of features to retain.
• score_func — the scoring function; currently only ScoreFunc::FClassif is available.

pub fn k(&self) -> usize

Return k.

pub fn score_func(&self) -> ScoreFunc

Return the score function.

Trait Implementations

impl<F: Clone> Clone for SelectKBest<F>

fn clone(&self) -> SelectKBest<F>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<F: Debug> Debug for SelectKBest<F>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<F: Float + Send + Sync + 'static> Fit<ArrayBase<OwnedRepr<F>, Dim<[usize; 2]>>, ArrayBase<OwnedRepr<usize>, Dim<[usize; 1]>>> for SelectKBest<F>

fn fit( &self, x: &Array2<F>, y: &Array1<usize>, ) -> Result<FittedSelectKBest<F>, FerroError>

Fit by computing per-feature ANOVA F-scores against the class labels.

Errors

• FerroError::InsufficientSamples if the input has zero rows.
• FerroError::InvalidParameter if k exceeds the number of features.
• FerroError::ShapeMismatch if x and y have different numbers of rows.

type Fitted = FittedSelectKBest<F>

The fitted model type returned by fit.

type Error = FerroError

The error type returned by fit.

impl<F: Float + Send + Sync + 'static> PipelineTransformer<F> for SelectKBest<F>

fn fit_pipeline( &self, x: &Array2<F>, y: &Array1<F>, ) -> Result<Box<dyn FittedPipelineTransformer<F>>, FerroError>

Fit using the pipeline interface.

The continuous y labels are rounded to usize class indices.

Errors

Propagates errors from Fit::fit.