[R] Odp: Select top three values from data frame
petr.pikal at precheza.cz
Wed Aug 26 11:38:01 CEST 2009
r-help-bounces at r-project.org napsal dne 26.08.2009 10:36:22:
> I'm trying to find an easy way to do this.
> I want to select the top three values of a specific column in a subset
> of rows in a data.frame. I'll demonstrate.
> A B C
> x 2 1
> x 4 1
> x 3 2
> y 1 5
> y 2 6
> y 3 8
> I want the top 3 values of B from the data.frame where A=X and C <2
> I could extract all the rows where C<2, then sort by B, then take the
> first 3. But that seems like the wrong way around, and it also will get
> messy with real data of over 100 columns.
One way is to use subset, order and head
head(subset(your.data[order(your.data$B, decreasing=T),], subset = C<2 &
> Any suggestions?
> R-help at r-project.org mailing list
> PLEASE do read the posting guide
> and provide commented, minimal, self-contained, reproducible code.
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