Reducing

Pivot reducing

Each Pivot group can be collapsed into a single row and then concatenated into a new DataRow with these row values (or their derived representation) with pivot keys as top-level columns or as column groups.

Reducing is a specific case of aggregation.

First, choose a Pivot reducing method:

• first, last — take the first or last row (optionally, the first or last one that satisfies a predicate) of each group;

• minBy / maxBy — take the row with the minimum or maximum value of the given RowExpression evaluated on rows within each group;

• medianBy / percentileBy — take the row at the position closest to the estimated median/percentile index of the RowExpression's results calculated on rows within each group.

These functions return a ReducedPivot, which can then be transformed into a new DataFrame containing a single combined row (either using the original reduced rows or their transformed versions) through one of the following methods:

• values — creates a new row containing the values from the reduced rows in the selected columns and produces a DataRow of these values;

• with — computes a new value for each reduced row using a RowExpression, and produces a DataRow containing these computed values.

Each method returns a new DataRow with pivot keys as top-level columns (or as column groups) and values composed of the reduced results from each group.

Check out Pivot grammar.

For more information: See "Pivot Reducing" on the documentation website.