The $partialdiff sub X$ [ IRI NOAA-VECTOR R0FCST R0FCST_DJF20182019 ] 2.5 months data are available as a columnar table,
i.e. as multiple columns of data, intended primarily to be read. However,
if you have other intentions for this table, or simply do not like the default choices, you may want to choose from the columnar tables with options.