Confusing error message for [[.factor (PR#14209)

Full_Name: George Russell
Version: 2.10.0 and 2.11.0 Under development (unstable) (2010-02-08 r51108)
OS: Windows
Submission from: (NULL) (217.111.3.131)

c("a","b")[[c(TRUE,FALSE)]]
Error in `[[.default`(factor(c("a", "b")), c(TRUE, FALSE)) : 
  recursive indexing failed at level 1

I find this error message confusing, though after reading the HELP carefully I
think I know what is going on. Would not something like "[[ does not work with
logical index vectors" be more appropriate?
It didn't take particularly careful reading to find this:

  "The most important distinction between [, [[ and $ is that
   the [ can select more than one element whereas the other two
   select a single element."

Try this:

  c("a","b")[[c(1,2)]]
  c("a","b")[[TRUE]]

  -Peter Ehlers
sessionInfo is (for 2.11) :
R version 2.11.0 Under development (unstable) (2010-02-08 r51108) 
i386-pc-mingw32 

locale:
[1] LC_COLLATE=German_Germany.1252  LC_CTYPE=German_Germany.1252   
LC_MONETARY=German_Germany.1252
[4] LC_NUMERIC=C                    LC_TIME=German_Germany.1252    

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

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Peter Ehlers
University of Calgary

Confusing error message for [[.factor (PR#14209)

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