Enum OneHotDrop 

pub enum OneHotDrop {
    None_,
    First,
    IfBinary,
}

Which category (if any) to drop from each feature’s one-hot block at transform time (OneHotEncoder(drop=...)).

Mirrors scikit-learn’s OneHotEncoder(drop=...) parameter, whose _parameter_constraints accepts {'first', 'if_binary'}, an array-like, or None (sklearn/preprocessing/_encoders.py:730, default None). Dropping a category removes one output column per feature, which is useful to break the collinearity an unregularized linear model would otherwise see (_encoders.py:498-516).

ferrolearn ships the None/'first'/'if_binary' modes (REQ-5). The array-of-explicit-categories form (drop[i] = the category to drop in feature i, _encoders.py:515-516) is NOT-STARTED.

The variant is named None_ (not None) to avoid colliding with Option::None.

Variants

None_

Retain all categories — no column is dropped (scikit-learn’s default drop=None, _encoders.py:509,:812-813: drop_idx_ = None). The default here too.

First

Drop the first category of every feature (scikit-learn’s drop='first', _encoders.py:510-511,:815-816: drop_idx_[j] = 0 for every feature). A feature with only one category is dropped entirely (its block width becomes 0).

IfBinary

Drop the first category of every feature that has exactly two categories, leaving 1-category and 3+-category features intact (scikit-learn’s drop='if_binary', _encoders.py:512-514,:817-831: drop_idx_[j] = 0 iff len(categories_[j]) == 2, else None).

Trait Implementations

impl Clone for OneHotDrop

fn clone(&self) -> OneHotDrop

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for OneHotDrop

impl Debug for OneHotDrop

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

Formats the value using the given formatter.

impl Default for OneHotDrop

fn default() -> OneHotDrop

Returns the “default value” for a type.

impl Eq for OneHotDrop

impl PartialEq for OneHotDrop

fn eq(&self, other: &OneHotDrop) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for OneHotDrop