On Fri, 27 Jul 2001, Vadim Ogranovich wrote:
> Dear S-Users, I tapply "summary" function to a vector and get back a list of
> vectors of length six as a result. So far so good. Then I want to convert
> this list to a data frame (actually to a matrix)and instead of getting a 2*6
> data frame I have a 1*12 one. Any suggestion why? Thanks, Vadim
> class(l[[1]])
[1] "table"
> dim(l[[1]])
[1] 1 6
which also explains the printout as characters. You should expect 6x2, I
think, no 2x6.
l <- tapply(x, f, function(x) as.vector(summary(x)))
$FALSE:
[1] 2.0 6.5 11.0 11.0 15.5 20.0
$TRUE:
[1] 1.0 5.5 10.0 10.0 14.5 19.0
> data.frame(l)
FALSE TRUE
1 2.0 1.0
2 6.5 5.5
3 11.0 10.0
4 11.0 10.0
5 15.5 14.5
6 20.0 19.0
(I'd use as.data.frame, BTW.) I'll leave you to work out how to preserve
the names.
>
>
> > x <- seq(1,20)
> > f <- rep(c(T,F), 10)
> > l <- tapply(x, f, summary)
> > l
> $FALSE:
> Min. 1st Qu. Median Mean 3rd Qu. Max.
> " 2.0" " 6.5" "11.0" "11.0" "15.5" "20.0"
>
> $TRUE:
> Min. 1st Qu. Median Mean 3rd Qu. Max.
> " 1.0" " 5.5" "10.0" "10.0" "14.5" "19.0"
>
> > data.frame(l)
> [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
> 2 6.5 11 11 15.5 20 1 5.5 10 10 14.5 19
> > mode(l)
> [1] "list"
> > class(l)
> [1] "named"
>
>
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--
Brian D. Ripley, ripley@stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
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