cor/group by???

Peter Dalgaard · 2006-02-01T21:18:22Z

bin999 at lycos.com writes: > Can someone help me calculate correlations for grouped values? > > Heres what my first few line of data look like: > > > head(cmexpr) > LLID GMID CEXPR MEXPR > 1 1005 10831 2.057462 -0.08486 > 2 1005 10831 2.057515 -0.08486 > 3 1005 10831 2.057462 0.01209 > 4 1005 10831 2.057515 0.01209 > 5 1005 10836 2.050980 0.17237 > 6 1005 10836 2.018576 0.17237 > > LLID is gene id, GMID is cell line id, the EXPR columns are gene expression is two different micr

Peter Dalgaard

Wed, Feb 1, 2006 1:18 PM

bin999 at lycos.com writes:

You're passing a function to by() whose result does not depend
on the argument x ...

This might be clearer:

c(by(cmexpr, cmexpr$LLID, with, cor(CEXPR, MEXPR, use="pair")))

or

sapply(split(cmexpr, cmexpr$LLID), with, cor(CEXPR, MEXPR, use="pair"))

O__  ---- Peter Dalgaard             ??ster Farimagsgade 5, Entr.B
  c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
 (*) \(*) -- University of Copenhagen   Denmark          Ph:  (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)                  FAX: (+45) 35327907

cor/group by???

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