Hi Ralf,
Perhaps the following is what you are looking for:
d <- data.frame(timestamp=c(3,3,3,5,8),
mylabel=c("a","a","a","b","c"))
d
d[!duplicated(d$timestamp),]
HTH,
Jorge
On Fri, Jul 30, 2010 at 12:18 AM, Ralf B <> wrote:
> I have to deal with data frames that contain multiple entries of the
> same (based on an identifying collumn 'id'). The second collumn is
> mostly corresponding to the the id collumn which means that double
> entries can be eliminated with ?unique.
>
> a <- unique(data.frame(timestamp=c(3,3,3,5,8),
>
mylabel=c("a","a","a","b","c")))
>
> However sometimes I have dataframes like this:
>
> a <- unique(data.frame(timestamp=c(3,3,3,5,8),
>
mylabel=c("a","z","a","b","c")))
>
> which then results in:
>
> timestamp mylabel
> 1 3 a
> 2 3 z
> 4 5 b
> 5 8 c
>
> However, I want only the first occurance of timestamp and then
> selected over the first label resulting in an output like this:
>
> timestamp mylabel
> 1 3 a
> 4 5 b
> 5 8 c
>
> Is there something like groupBy (like in SQL) ?
>
> Best,
> Ralf
>
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