Compress Selected Columns

To minimize the size of a large data table, use the Compress Selected Columns message. Each column is compressed into the most compact form.

dt << Compress Selected Columns( {column name, column name} );

For example, compress the age, sex, height, and weight columns in Big Class.jmp as follows:

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

dt << Compress Selected Columns(

{:age, :sex, :height, :weight}

);