Hi,

I seem to be getting different results depending on if I use select() or
mget() with the hgu133plus2.db package for a probe with a 1 probe to many
gene mapping. Does anyone know why there is a discrepancy?

> select(hgu133plus2.db, keys="213801_x_at", cols=c("ENTREZID", "SYMBOL"),
keytype="PROBEID")
      PROBEID ENTREZID  SYMBOL
1 213801_x_at     3921    RPSA
2 213801_x_at   388524 RPSAP58
3 213801_x_at   574040  SNORA6
4 213801_x_at     6044 SNORA62
5 213801_x_at   653162  RPSAP9
6 213801_x_at   730029 RPSAP19
Warning message:
In .generateExtraRows(tab, keys, jointype) :
  'select' resulted in 1:many mapping between keys and return rows

> mget("213801_x_at", hgu133plus2ENTREZID)
$`213801_x_at`
[1] NA

> sessionInfo()
R version 3.0.0 (2013-04-03)
Platform: x86_64-unknown-linux-gnu (64-bit)

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
 [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
 [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8
 [7] LC_PAPER=C                 LC_NAME=C
 [9] LC_ADDRESS=C               LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C

attached base packages:
[1] parallel  stats     graphics  grDevices utils     datasets  methods
[8] base

other attached packages:
[1] hgu133plus2.db_2.9.0 org.Hs.eg.db_2.9.0   RSQLite_0.11.3
[4] DBI_0.2-6            AnnotationDbi_1.22.3 Biobase_2.20.0
[7] BiocGenerics_0.6.0   limma_3.16.2

loaded via a namespace (and not attached):
[1] IRanges_1.18.0 stats4_3.0.0   tools_3.0.0

Thanks,
Christina
-- 
Christina Chaivorapol, Ph.D.
Genentech, Inc.
Bioinformatics & Computational Biology
chrichai@gene.com

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