MapDocs

The Map Operation

Computes a new value for every value, row, or key–group pair of the receiver, and collects the results.

The functions of this family share the name but differ in what they go over and what they give back:

• map and mapIndexed — go over the values of a DataColumn and return a DataColumn of the same size.

• map — goes over the rows of a DataFrame and returns a List.

• mapToColumn — goes over the rows of a DataFrame and returns a single DataColumn that is not part of that DataFrame.

• mapToFrame — returns a new DataFrame made of the columns described in an AddDsl.

• map — goes over the key–group pairs of a GroupBy and returns a List.

• mapToRows — goes over the key–group pairs of a GroupBy and returns a DataFrame.

• mapToFrames — goes over the key–group pairs of a GroupBy and returns a FrameColumn.

Each result keeps the order of the values, rows, or key–group pairs it was computed from.

See also:

• add — computes a new column in the same way, and returns the DataFrame with that column added to it, next to the ones it already had.

• expr — the same as mapToColumn, for use inside the Columns Selection DSL.

• convert — computes new values for the selected columns and replaces the old ones.

For more information: See map on the documentation website.