[R] Subsetting subsets of data.frames

[Uwe Ligges]

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Uwe Ligges

On 07.06.2010 09:01, Jeff08 wrote:
>
> Hey Everyone,
>
> I have been stumped by this all day.
>
> Basically, I have a data.frame of multiple columns. Of concern are "id"&
> "date"
>
> For some reason, oftentimes there are duplicates of data with the same date.
>
> I would like to remove the duplicates per different id (removing duplicate
> dates for the entire data.frame would leave nothing since different id's all
> have the same dates)
>
> subset(x,!duplicated(x$date_)) works for just one ID, but i am having
> trouble figuring out how to apply this to each subset of IDs (and retaining
> the original data.frame structure)