Summaries

Summaries allow users to easily see statistics on grouped data. Users may access information like the maximum value of columns in every group, or the sum of the items, median value, etc.

Essential Grouping lets users add one or multiple summary items for each group. Changes to any data items are automatically reflected in the summaries. The calculation of summary values is very fast with only O(log2 n) operations (with n being the number of records in the table) because of highly optimized balanced tree structures used in the grouping engine.

The following graphic represents a code window illustrating how to add a summary item.

After adding a summary item, the Element collection in the Grouping Engine has additional items at the bottom of each group. The picture below shows the elements for a table that has been grouped by column C, with summary items on column A (Count and MaxLength) and on column D (Count and Values vector).

The Grouping Engine has several built-in summaries such as:

*Int32Aggregate DoubleAggregate (Count, Min, Max, Sum) StringAggregate (MaxLength, Count) Count DistinctCount (Count, Values array) Vector (Values) DoubleVector (statistical methods: Median, Min, Max, 25% Quartile, 75% Quartile).

The engine supports summaries that operate on vectors such as Distinct Count, Median, 25% and 75% Quartile. Custom summaries may easily be added.