Contents

aggregated(on:naming:transform:)

Generates a data frame by aggregating each group’s contents for each column you select by name.

Declaration

func aggregated<Element, Result>(on columnNames: [String], naming: (String) -> String, transform: (DiscontiguousColumnSlice<Element>) throws -> Result?) rethrows -> DataFrame

Parameters

  • columnNames:

    A comma-separated, or variadic, list of column names.

  • naming:

    A closure that converts a column name to another name.

  • transform:

    A closure that aggregates a group’s elements in a specific column.

Discussion

The data frame contains two columns that:

  • Identify each group

  • Store the results of your aggregation transform closure

See Also

Aggregating a Row Grouping