[R] Newbie: Subsets of data frame

[Morten Sickel]

I feel a bit embarassed by this, but I have not managed to find out how:

I have a data frame containing measurements over time for a number of
different locations:

> str(milk)
`data.frame':   845 obs. of  3 variables:
 $ date    : num  1987 1987 1987 1987 1987 ...
 $ value   : num  5 1 2 5 1 1 2 3 2 4 ...
 $ location: Factor w/ 36 levels "Alta","Andøy",..: 1 1 1 1 1 1 1 1 1 1 ...

I assume there is some simpe way of extracting subsets of the data frame for
analysing the time series for just one of the location, but how? I have
tried using various variants of extract, [] and subset, but obiously, I have
missed something, for I have not managed to get out what I want. 

-- 
Morten Sickel
Norwegian Radiation Protection Authority 

-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-help-request at stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._