Compress Selected Columns
JMP lets you compress columns in a data table to minimize the size of the file and reduce the
amount of memory required to analyze data. This feature is helpful when numeric columns
contain many small integers or when any column contains fewer than 255 unique values. For
example, compressing columns in a data table with 389 columns and 85,000 rows might
decrease the file size from 250MB to 33MB, depending on the type of data.
dt = Open( "$SAMPLE_DATA/Big Class.jmp" );
dt << Compress Selected Columns(
{:age, :sex, :height, :weight}
);