[Rd] Apparent bug in summaryBy (PR#13941)

[paterno at fnal.gov]

Full_Name: Marc Paterno
Version: 2.9.2
OS: Mac OS X 10.5.8
Submission from: (NULL) (99.53.212.55)


summaryBy() produces incorrect results when given some data  frames. Below is a
transcript of a session showing the result, in a data frame with 2 observations
of 2 variables.
-------------------
thomas:999 paterno$ R --vanilla

R version 2.9.2 (2009-08-24)
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ISBN 3-900051-07-0

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> library(doBy)
> tmp = read.table("moduledata_999_1.txt",header=FALSE)
> str(tmp)
'data.frame':	2 obs. of  2 variables:
 $ V1: Factor w/ 2 levels "b","c": 2 1
 $ V2: num  1 2
> tmp
  V1 V2
1  c  1
2  b  2
> summaryBy(V2~V1,tmp)
  V1 V2.mean
1  b       1
2  c       2