MoEx-1_0-st-v1.r2.pgf contains the mapping from probe_id to probeset_id. But it is not straightforward to be parsed by basic R functions. Since oligo package processes Exon Array, there must be a way to get the mapping from oligo package. But I don't find such information on http://www.bioconductor.org/packages/2.5/bioc/manuals/o ligo/man/oligo.pdf. Could somebody let me know how I should get the mapping information?