Question: How to apply nested group-bys?

[Jefftopia]

How can I achieve the following structure? (Nested group-by).

Color	State	Name	Qty	Value
Red
	VA
		Jeff	2	$10
		John	1	$5
	PA
		Rachel	4	$20
Blue
	VA
		Robert	5	$100
	PA
		Rebecca	3	$40

I have now something like the following:

    private recurseDataFrame(dataFrame: DataFrame | IGroupedDataFrame, group: IGroupByField, agg: IAggregateField): DataFrame {
        if (dataFrame instanceof DataFrame) {

            if (agg) {

                return dataFrame
                    .groupBy(...<string[]> group.name)
                    .aggregate((group) => dataFrame.stat[mathMap[agg.type]](agg.name));
            }

            return dataFrame.groupBy(...<string[]> group.name);

        } else {
            for (const dfGroup of dataFrame) {
                dfGroup.group = this.recurseDataFrame(dfGroup.group, group, agg);
            }

            return dataFrame;
        }
    }

One issue I have is that for (const dfGroup of dataFrame) is not normally supported by TypeScript when compiling to es5. By default, TypeScript only supports Array types for a for let or for const.

Enabling down-compilation of iterators causes other issues with the Angular framework, so it isn't a good solution for me,

Edit:

Is it as simple as:

            for (const dfGroup of dataFrame.toCollection()) {
                dfGroup.group = this.recurseDataFrame(dfGroup.group, group, agg);
            }

[Gmousse]

@Jefftopia Hi, have you resolved your computation issue ?

If you need to iterate on each groups of a groupedDataFrame you can use .toCollection (similar to [...yourGroupedDataFrame]).

It's also possible to groupBy inside an aggregate: df.groupBy(...).aggregate(gdf => gdf.groupBy(...).aggregate(...)) or to group on multiple keys (think tidy data instead of nested one).

Refers to: https://gmousse.gitbooks.io/dataframe-js/doc/api/groupedDataframe.html

[Jefftopia]

Thanks, I resolved the issue.

[mike-incipia]

Refers to: https://gmousse.gitbooks.io/dataframe-js/doc/api/groupedDataframe.html

@Gmousse, it seems the documentation content for GroupedDataFrame at the docs link is not being populated (I see an empty section when I load it). Is it possible that the page location has changed or something like that?

By the way, thank you for the info in this thread about working with GroupedDataFrames!