try this:
> x <- data.frame(day=rep(1:10, each=4), site=rep(sample(101:104, 10, TRUE),
each=4))
> s.f <- function(start){
+ start <- start[1] + 0:3 # generate the sequence
+ ifelse(start > 104, start - 4, start)
+ }
> x$siteNew <- ave(x$site, x$day, FUN=s.f)
> x
day site siteNew
1 1 104 104
2 1 104 101
3 1 104 102
4 1 104 103
5 2 101 101
6 2 101 102
7 2 101 103
8 2 101 104
9 3 103 103
10 3 103 104
11 3 103 101
12 3 103 102
13 4 101 101
14 4 101 102
15 4 101 103
16 4 101 104
17 5 102 102
18 5 102 103
19 5 102 104
20 5 102 101
21 6 102 102
22 6 102 103
On Mon, Mar 15, 2010 at 1:45 PM, Hosack, Michael <mhos...@state.pa.us>wrote:
> Hey folks,
>
> I have a difficult (at least for me) problem that I was hoping
> one of you may know how to solve. I want to assign a sequence
> to subsets of a variable in a data frame based on date.
> The variable is 'SITE1' and the date is a unique day (DD) and
> month (MM) combination. The sequence contains site numbers 101:104,
> and each day-month combination takes four site numbers from that
> sequence in an order dependent upon which site number is listed.
> For example, I need a sequence of 101,102,103,104 if 101 is the
> number listed, 102,103,104,101 if 102 is the number listed, 104,101,
> 102,103 if the 104 is the number listed for a given DD MM combination,
> etc. As a further example, for every sequence that happens to be
> 102,102,102,102
> for a MM DD combination I want to replace it with 102,103,104,101.
> Please see the attached partial dataframe. Any help would be
> greatly appreciated. I have tried creating a function using seq()
> and then using ddply, and also writing a loop with no luck.
>
> Mike
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
> and provide commented, minimal, self-contained, reproducible code.
>
>
--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem that you are trying to solve?
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