Struct OneHotEncoder 

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

An unfitted one-hot encoder for multi-column categorical data.

Input: Array2<usize> where each column contains non-negative integer category indices. Calling Fit::fit learns the set of categories per column and returns a FittedOneHotEncoder.

Examples

use ferrolearn_preprocess::OneHotEncoder;
use ferrolearn_core::traits::{Fit, Transform};
use ndarray::array;

let enc = OneHotEncoder::<f64>::new();
let x = array![[0usize, 1], [1, 0], [2, 1]];
let fitted = enc.fit(&x, &()).unwrap();
let encoded = fitted.transform(&x).unwrap();

Implementations

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

pub fn new() -> Self

Create a new OneHotEncoder.

Trait Implementations

impl<F: Clone> Clone for OneHotEncoder<F>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<F: Debug> Debug for OneHotEncoder<F>

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

Formats the value using the given formatter.

impl<F: Float + Send + Sync + 'static> Default for OneHotEncoder<F>

fn default() -> Self

Returns the “default value” for a type.

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

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

Fit the encoder by determining the number of unique categories per column.

The number of categories for column j is max(x[:, j]) + 1.

Errors

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

type Fitted = FittedOneHotEncoder<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<usize>, Dim<[usize; 2]>>> for OneHotEncoder<F>

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

Fit the encoder on x and return the one-hot encoded output in one step.

Errors

Returns an error if fitting or transformation fails.

type FitError = FerroError

The error type for the combined fit-transform operation.

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

Implement Transform on the unfitted encoder to satisfy the FitTransform: Transform supertrait bound. Calling transform on an unfitted encoder always returns an error.

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

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

Use Fit::fit to produce a FittedOneHotEncoder, 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.