Get rows currently displayed on a dendrogram

anne_sa

Hello,

 

I would like to know if there is a way to know which individuals are currently displayed on a dendrogram after a zooming action.

 

Here is an example:

 

Names Default To Here( 1 );
dt = Open( "$SAMPLE_DATA/Birth Death Subset.jmp" );
Hierarchical Cluster(
	Y( :birth, :death ),
	Label( :country ),
	Method( "Ward" ),
	Standardize Data( 1 ),
	Dendrogram Scale( "Distance Scale" ),
	Number of Clusters( 4 ),
	SendToReport(
		Dispatch( {}, "Dendrogram", OutlineBox, {SetHorizontal( 1 )} ),
		Dispatch(
			{"Dendrogram"},
			"2",
			ScaleBox,
			{Min( 18 ), Max( 31 ), Inc( 5 ), Minor Ticks( 0 )}
		)
	)
);

I would like to get the list of the 13 countries selected.

A good solution, I think, would be to get the min and max values (18 and 31) but so far I can't find how to extract them...

 

Thanks in advance for your help!

jules

Hi @anne_sa,

I don't know of a direct way to get those rows, but since the Min and Max information is part of the script for the platform, and because we can save the display order of the rows in the dendrogram, we can script our way to the result with a little work. It's not altogether elegant, but here's one way I came up with:

Names Default To Here( 1 );
dt = Open( "$SAMPLE_DATA/Birth Death Subset.jmp" );


hcPlatform = Hierarchical Cluster(
	Y( :birth, :death ),
	Label( :country ),
	Method( "Ward" ),
	Standardize Data( 1 ),
	Dendrogram Scale( "Distance Scale" ),
	Number of Clusters( 4 ),
	SendToReport(
		Dispatch( {}, "Dendrogram", OutlineBox, {SetHorizontal( 1 )} ),
		Dispatch( {"Dendrogram"}, "2", ScaleBox, {Min( 18 ), Max( 31 ), Inc( 5 ), Minor Ticks( 0 )} )
	)
);


//save the order displayed in the platform
displayOrd = hcPlatform << Save Display Order;

//get the script, which contains the Min() and Max() information
exprPlat = hcPlatform << Get Script;

//Extract the Min and Max. This is indexed in the reverse of the Display Order
//that is, the max value is the first in the order (as if it is an axis), so subtracting
//this value from the number of rows in the table brings things into alignment

minOrder = 1 + N Rows( dt ) - Arg( Extract Expr( exprPlat, Max( Wild() ) ) );
maxOrder = N Rows( dt ) - Arg( Extract Expr( exprPlat, Min( Wild() ) ) );

//select the rows in the table that meet the condition of being in the randge displayed
dt << Select Where( And( As Column( displayOrd ) >= minOrder, As Column( displayOrd ) <= maxOrder ) );

//get the matrix of row numbers for the selected rows, i.e., rows displayed in zoom
matchingRows = dt << get selected rows;

I hope this helps!

@jules