[R] Odp: Subsetting subsets of data.frames

[Petr PIKAL]

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) 
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> subsets-of-data-frames-tp2245556p2245556.html
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