[source] # One Hot Encoder The One Hot Encoder takes a categorical feature column and produces an n-dimensional continuous representation where *n* is equal to the number of unique categories present in that column. A `0` in any location indicates that the category represented by that column is not present in the sample, whereas a `1` indicates that a category is present. **Interfaces:** [Transformer](api.md#transformer), [Stateful](api.md#stateful), [Persistable](../persistable.md) **Data Type Compatibility:** Categorical ## Parameters This transformer does not have any parameters. ## Example ```php use Rubix\ML\Transformers\OneHotEncoder; $transformer = new OneHotEncoder(); ``` ## Additional Methods Return the categories computed during fitting indexed by feature column: ```php public categories() : ?array ```