Scripting Guide > Data Tables > Advanced Data Table Scripting > Stack Values in a Data Table
Publication date: 08/13/2020

Stack Values in a Data Table

Stack() combines values from several columns into one column.

dt << Stack(
	Columns ( columns ),  // the columns to stack together
	Source Label Column ( "name" ), // to identify source columns
	Stacked Data Column ( "name" ), // name for the new stacked column
	Number of Series( n ), // stacks selected columns into two or more columns
	Contiguous, // specifies that the series consists of adjacent columns
	Keep ( columns ), // the columns to keep in the data table
	Drop ( columns ), // the columns to drop in the data table
	Output Table ( "name" ), // the name for the new data table
	Columns( columns ) ), // specify which columns to include in the stacked table
	Copy Formula( Boolean ), // copy the formula into the stacked column
	Drop All Other Columns( Boolean ), // omit the non-stacked columns from the new table
	Name( "non-stacked columns" )( Keep( col1, ... ) // the non-stacked columns to keep
	Name( "non-stacked columns" )( Drop( col1, ... ) // the non-stacked columns to omit
	Suppress Formula Evaluation( Boolean ) // do not evaluate the formula

For example, the following script stacks the weight and height columns in Big Class.jmp:

dt = Open( "$SAMPLE_DATA/Big Class.jmp" );
StackedDt = dt << Stack(
    Columns( :weight, :height ),
    Source Label Column( "ID" ),
    Stacked Data Column( "Y" ),
    Name( "Non-stacked columns" )( Keep( :age, :sex ) ),
    Output Table( "Stacked Table" )
);

The Columns(columns) argument can take a list of columns, or an expression that evaluates to a list.

You can also stack multiple sets of columns into multiple columns.

dt = Open( "$SAMPLE_DATA/Blood Pressure.jmp" );
dt << Stack(
	Columns(
		:BP 8M,
		:BP 12M,
		:BP 6M,
		:BP 8W,
		:BP 12W,
		:BP 6W,
		:BP 8F,
		:BP 12F,
		:BP 6F
	),
	Stacked Data Column( "BP" ),
	Source Label Column( "Day" ),
	Number of Series( 3 ), // number of sets in each series
	Contiguous, /* If you want to stack vertically. Otherwise, omit the argument. */
 
);
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