To delete columns, send a Delete Columns message and specify which column or columns to delete. To delete more than one column, list the columns as multiple arguments or as a list.
dt = Open( "$SAMPLE_DATA/Big Class.jmp" );
dt << Delete Columns( "weight" );
dt << Delete Columns( "weight", "age", "sex" );
dt << Delete Columns( {"weight", "age", "sex"} );
Without an argument, Delete Columns deletes columns that were previously selected. See Column Attributes.
dt = Open( "$SAMPLE_DATA/Big Class.jmp" );
Column("age") << Set Selected;
dt << Delete Columns();