Dear Jim and Henrique,
thank you both for your help. I have done this but run into another problem:
In the example below "loc1,loc2" occurs in the (now correct, thanks to your
advice) "list" twice.
trips=("loc1,loc2","loc2,loc3")
DF$listoftrips=("loc1,loc2", "loc1,loc3", "loc2,loc3","loc1,loc2").
I am now using
DF$Data[match(trips,listoftrips)] to get Data associated with the trips listed
in "trips".
My problem is that multiple matches occur and match() seems to yield only the
first match. I am interested in all matches per trip and actually would like to
find the mean of DF$Data associated with each trip listed in "trips".
I have searched the help files and believe that the solution is aggregate()
rather than match(), but I haven't quite figured out how to apply it for this
example.
mean(DF$Data[match(trips,listoftrips)]) gives the mean for all trips, so that's
not right. How can I get means for all trips in "trips" ???
Many thanks for any suggestions.
Juliane
Dr. Juliane Struve
Environmental Scientist
10, Lynwood Crescent
Sunningdale SL5 0BL
01344 620811
----- Original Message ----
From: jim holtman <[email protected]>
To: Juliane Struve <[email protected]>
Cc: [email protected]
Sent: Friday, 18 September, 2009 15:02:47
Subject: Re: [R] matching pairs regardless of order
Here is an example:
> x <- c('loc1,loc2', 'loc2,loc3', 'loc2,loc1', 'loc3,loc1')
> x.s <- strsplit(x, ',')
> # now sort them
> x.s <- sapply(x.s, sort)
> # create new output
> unique(apply(x.s, 2, paste, collapse=','))
[1] "loc1,loc2" "loc2,loc3" "loc1,loc3"
>
On Fri, Sep 18, 2009 at 8:47 AM, Juliane Struve
<[email protected]> wrote:
> Dear list,
>
> I am using match() to match pairs of locations, e.g. trip="loc1,loc2" from a
> list of such pairs, e.g. list=("loc1,loc2", "loc1,loc3",
> "loc2,loc3","loc2,loc1").
>
> In this example match() will match "trip" with the first element of "list",
> but not the 4th, because the order is reversed.
>
> How can I get a match with both ?
>
> Many thanks for any help,
>
> Juliane
>
>
>
>
> ______________________________________________
> [email protected] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 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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