[R] by group problem
ggrothendieck at gmail.com
Fri Aug 31 15:52:40 CEST 2007
See the examples labelled head in the examples section near the bottom of:
These show show to do it using order as well as using SQL via sqldf.
On 8/31/07, Cory Nissen <cnissen at akoyainc.com> wrote:
> I am working with census data. My columns of interest are...
> PercentOld - the percentage of people in each county that are over 65
> County - the county in each state
> State - the state in the US
> There are about 3100 rows, with each row corresponding to a county within a state.
> I want to return the top five "PercentOld" by state. But I want the County and the Value.
> I tried this...
> topN <- function(column, n=5)
> column <- sort(column, decreasing=T)
> top5PerState <- tapply(data$percentOld, data$STATE, topN)
> But this only returns the value for "percentOld" per state, I also want the corresponding County.
> I think I'm close, but I just can't get it...
> [[alternative HTML version deleted]]
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> and provide commented, minimal, self-contained, reproducible code.
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