Function subset

subset(
    data: DataFrame,
    keep:
        | readonly (boolean | null)[]
        | ((row: DataRow) => boolean | null | undefined),
    options?: SubsetOptions,
): DataFrame
The rows of a data frame that meet a condition, and optionally some of its columns. Equivalent to R's subset(). For a data frame: keep is a boolean per row or a function of the row; a missing (null) or non-boolean result counts as false, as R drops the rows whose condition is NA.
Parameters
- data: DataFrame
- keep: readonly (boolean | null)[] | ((row: DataRow) => boolean | null | undefined)
- options: SubsetOptions = {}
Returns DataFrame
Example
```
const d = { y: [5, NaN, 7, 2], g: ["a", "b", "a", "b"] };
subset(d, (row) => (row.y as number) > 4);         // { y: [5, 7], g: ["a", "a"] }
subset(d, [true, true, false, false], { select: ["g"] }); // { g: ["a", "b"] }
```
- Defined in descriptive/dataFrames.ts:359