Struct SimpleImputer 

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

An unfitted simple imputer.

Calling Fit::fit computes the per-column fill values according to the chosen ImputeStrategy and returns a FittedSimpleImputer that can transform new data by replacing NaN values with those fill values.

NaN values are ignored when computing statistics during fitting — e.g. the Mean strategy computes the mean of only the non-NaN elements.

Examples

use ferrolearn_preprocess::imputer::{SimpleImputer, ImputeStrategy};
use ferrolearn_core::traits::{Fit, Transform};
use ndarray::array;

let imputer = SimpleImputer::<f64>::new(ImputeStrategy::Mean);
let x = array![[1.0, f64::NAN], [3.0, 4.0], [5.0, 6.0]];
let fitted = imputer.fit(&x, &()).unwrap();
let out = fitted.transform(&x).unwrap();
// NaN in column 1 row 0 is replaced with the mean of column 1 = (4+6)/2 = 5.0
assert!((out[[0, 1]] - 5.0).abs() < 1e-10);

Implementations

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

pub fn new(strategy: ImputeStrategy<F>) -> Self

Create a new SimpleImputer with the given strategy.

pub fn strategy(&self) -> &ImputeStrategy<F>

Return the imputation strategy.

Trait Implementations

impl<F: Clone> Clone for SimpleImputer<F>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<F: Debug> Debug for SimpleImputer<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]>>, ()> for SimpleImputer<F>

fn fit( &self, x: &Array2<F>, _y: &(), ) -> Result<FittedSimpleImputer<F>, FerroError>

Fit the imputer by computing per-column fill values.

NaN values are excluded from the statistic computation. Columns that are entirely NaN at fit time are filled with F::zero() for Mean and Median, and F::zero() for MostFrequent.

Errors

Returns FerroError::InsufficientSamples if the input has zero rows.

type Fitted = FittedSimpleImputer<F>

The fitted model type returned by fit.

type Error = FerroError

The error type returned by fit.

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

fn fit_transform(&self, x: &Array2<F>) -> Result<Array2<F>, FerroError>

Fit the imputer on x and return the imputed output in one step.

Errors

Returns an error if fitting fails (e.g. zero rows).

type FitError = FerroError

The error type for the combined fit-transform operation.

impl PipelineTransformer for SimpleImputer<f64>

fn fit_pipeline( &self, x: &Array2<f64>, _y: &Array1<f64>, ) -> Result<Box<dyn FittedPipelineTransformer>, FerroError>

Fit the imputer using the pipeline interface.

The y argument is ignored; it exists only for API compatibility.

Errors

Propagates errors from Fit::fit.

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

Implement Transform on the unfitted imputer to satisfy the FitTransform: Transform supertrait bound. Always returns an error.

fn transform(&self, _x: &Array2<F>) -> Result<Array2<F>, FerroError>

Always returns an error — the imputer must be fitted first.

Use Fit::fit to produce a FittedSimpleImputer, then call Transform::transform on that.

type Output = ArrayBase<OwnedRepr<F>, Dim<[usize; 2]>>

The transformed output type.

type Error = FerroError

The error type returned by transform.