Feature

```
public interface Feature
```
A feature in the formula once bound to a schema. A feature returns a single value when applied to a data object (e.g. Tuple).

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method and Description
`default BaseVector`	`apply(DataFrame df)`
`java.lang.Object`	`apply(Tuple o)` Applies the term on a data object.
`default boolean`	`applyAsBoolean(Tuple o)` Applies the term on a data object and produces an boolean-valued result.
`default byte`	`applyAsByte(Tuple o)` Applies the term on a data object and produces an byte-valued result.
`default char`	`applyAsChar(Tuple o)` Applies the term on a data object and produces an char-valued result.
`default double`	`applyAsDouble(Tuple o)` Applies the term on a data object and produces an double-valued result.
`default float`	`applyAsFloat(Tuple o)` Applies the term on a data object and produces an float-valued result.
`default int`	`applyAsInt(Tuple o)` Applies the term on a data object and produces an int-valued result.
`default long`	`applyAsLong(Tuple o)` Applies the term on a data object and produces an long-valued result.
`default short`	`applyAsShort(Tuple o)` Applies the term on a data object and produces an short-valued result.
`StructField`	`field()` Returns the meta data of feature.
`default boolean`	`isVariable()` Returns true if the term represents a plain variable/column in the data frame.

Interface Feature