[R] Odp: Subsetting subsets of data.frames

From: Petr PIKAL <petr.pikal_at_precheza.cz>
Date: Mon, 07 Jun 2010 14:33:44 +0200

Hi

some example would be helpful.

r-help-bounces_at_r-project.org napsal dne 07.06.2010 09:01:27:

>
> 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

However if above works on one id so use split sapply/lapply approach. Split your data according to id and use sapply or lapply wit above function for splitted object. I believe this is what ddply does so maybe it can be used too.

Regards
Petr

> trouble figuring out how to apply this to each subset of IDs (and
retaining
> the original data.frame structure)
> --
> View this message in context: http://r.789695.n4.nabble.com/Subsetting-
> subsets-of-data-frames-tp2245556p2245556.html
> Sent from the R help mailing list archive at Nabble.com.
>
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