Create Columns

To add a new column to a data table, send a New Column message to a data table reference. The first argument, the column’s name, is required. Either enclose the name in quotation marks or specify an expression evaluating to the name.

dt = Open( "MyData.jmp" );

dt << New Column( "wafer" );

a = "wafer";

dt << New Column( a );

If the table already includes a column by the same name, a sequential numeric value is appended to the new column name (wafer, wafer 2, wafer 3, and so on).

Unless otherwise specified, columns are numeric, continuous, and 10 characters wide.

•	Data type (numeric, character, or row state)

•	Analysis type (continuous, nominal, or ordinal)

•	Column width (only for numeric columns)

•	Numeric format

The following example creates a new column whose data type is numeric, analysis type is continuous, width is set to 5, and numeric format is set to Best:

dt << New Column( "wafer", Numeric, "Continuous", Format( "Best", 5 ) );

The following example creates a character column and automatically assigns the nominal analysis type.

dt << New Column( "Last Name", Character );

You can also add formulas and other script messages appropriate to the column.

dt = Open( "$SAMPLE_DATA\Big Class.jmp" );

dt << New Column( "Ratio", Numeric, "Continuous", Formula( :height/:weight ) );

dt << New Column( "myMarkers",

	Row State,

	Set Formula( Marker State( age - 12 ) )

);

If you plan to work with specific columns later (for example, grouping or changing data types), create a column reference, as follows:

myCol = dt << New Column( "Birth Date" );

Fill a Column with Data

To fill the column with data, use Values or its equivalent, Set Values. Include the value for each cell in a list.

The following example adds a new column called Last Name to a new data table. Three values are added: Smith, Jones, and Anderson.

dt = New Table( "My Data");

dt << New Column( "Last Name", Character, Values( {"Smith", "Jones", "Anderson"} ) );

The column can also be filled with numeric values. The following example adds a new column called Row Number to a new data table. The function N Row returns the number of rows in the table, and numeric values populate all of the rows in the column, beginning with 1.

dt = New Table( "My Data");

dt << New Column( "Row Number",

	Numeric,

	Values( 1 :: N Row() ),

	Format( "Best", 5 )

);

To add a column of random numbers, insert a formula along with the random function.

dt = Open( "$SAMPLE_DATA\Big Class.jmp" );

dt << New Column( "Random", Numeric, Formula( Random Uniform() ) );

Another option is to add a constant numeric value to each cell. In the following example, the number 5 is added to each cell.

dt << New Column( "Number" );

:Number << Set Each Value( 5 );

New Column() can also be used as a built-in function, in other words, without the << (Send) command applied to the data table reference. When used in this way, the column is added to the current data table.

dt << New Column( "Address" ); // command is sent to the data table reference

dt << New Column( "Address" ); // column is added to the current data table