[R] Problem with data.frame()

[Agustin Lobo]

Given
 > str(x)
'data.frame':	5284 obs. of  5 variables:
  $ COD  : chr  "0800101001" "0800101002" "0800101003" "0800101004" ...
  $ 0-4  : num  79 215 84 58 127 134 15 122 101 99 ...
  $ 5-9  : num  76 180 32 56 81 106 10 112 128 96 ...
  $ 10-14: num  68 145 39 46 78 81 8 92 142 107 ...
  $ 15-19: num  73 170 49 52 103 77 10 116 129 129 ...

I get

 > str(data.matrix(x))
  num [1:5284, 1:5] 8e+08 8e+08 8e+08 8e+08 8e+08 ...
  - attr(*, "dimnames")=List of 2
   ..$ : chr [1:5284] "3" "6" "9" "12" ...
   ..$ : chr [1:5] "COD" "0-4" "5-9" "10-14" ...

Should not data.matrix() return a numeric matrix?

And I'm even more confused by this:
 > x2 <- censocatT[,2:5]
 > str(x2)
'data.frame':	5284 obs. of  4 variables:
  $ 0-4  : num  79 215 84 58 127 134 15 122 101 99 ...
  $ 5-9  : num  76 180 32 56 81 106 10 112 128 96 ...
  $ 10-14: num  68 145 39 46 78 81 8 92 142 107 ...
  $ 15-19: num  73 170 49 52 103 77 10 116 129 129 ...
 > str(data.matrix(x2))
  num [1:5284, 1:4] 79 215 84 58 127 134 15 122 101 99 ...
  - attr(*, "dimnames")=List of 2
   ..$ : chr [1:5284] "3" "6" "9" "12" ...
   ..$ : chr [1:4] "0-4" "5-9" "10-14" "15-19"


Thanks for any clarification

Agus
-- 
Dr. Agustin Lobo
Institut de Ciencies de la Terra "Jaume Almera" (CSIC)
LLuis Sole Sabaris s/n
08028 Barcelona
Spain
Tel. 34 934095410
Fax. 34 934110012
email: Agustin.Lobo at ija.csic.es
http://www.ija.csic.es/gt/obster