[Rd] split.data.frame

[Romain Francois]

Hello,

I very much enjoy "with" and "subset" semantics for data frames and was 
wondering if we could have something similar with split, basically by 
evaluating the second argument "with" the data frame :

split.data.frame
function(x, f, drop = FALSE, ...){
         call <- match.call( )
         fcall <- call( "with", data = call[["x"]], expr = call[["f"]] )
         ff <- eval( fcall, parent.frame(1) )

         lapply(split(seq_len(nrow(x)), ff, drop = drop, ...), 
function(ind) x[ind, , drop = FALSE])
}


 > split( df, y )
$`1`
   x y
1 1 1
2 2 1
3 3 1
4 4 1
5 5 1

$`2`
     x y
6   6 2
7   7 2
8   8 2
9   9 2
10 10 2

 > split( df, x > 3 )
$`FALSE`
   x y
1 1 1
2 2 1
3 3 1

$`TRUE`
     x y
4   4 1
5   5 1
6   6 2
7   7 2
8   8 2
9   9 2
10 10 2


Romain

-- 
Romain Francois
Professional R Enthusiast
+33(0) 6 28 91 30 30
http://romainfrancois.blog.free.fr
|- http://tr.im/HlX9 : new package : bibtex
|- http://tr.im/Gq7i : ohloh
`- http://tr.im/FtUu : new package : highlight