of course!

Thanks,

baptiste

On 3 Apr 2009, at 14:48, hadley wickham wrote:

On Fri, Apr 3, 2009 at 8:43 AM, baptiste auguie <ba...@exeter.ac.uk> wrote:
That makes sense, so I can do something like,

count <- function(x){
       as.integer(unclass(table(x)))
}

count(d$user_id)

ddply(d, .(user_id), transform, count = count(user_id))

 user_id  website time count
1      20   google  930     2
2      20 facebook 1000     2
3      21    yahoo  935     1
4      25 facebook 1015     1
5      61   google  940     1

Have I missed a built-in function to obtain this result?

ddply(d, .(user_id), transform, count = nrow)

?

Hadley

--
http://had.co.nz/

_____________________________

Baptiste AuguiƩ

School of Physics
University of Exeter
Stocker Road,
Exeter, Devon,
EX4 4QL, UK

Phone: +44 1392 264187

http://newton.ex.ac.uk/research/emag

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