Re: [R] Unique observations
On Nov 25, 2009, at 9:44 AM, John Lipkins wrote: Hey R list, A beginners question. How can I do the following: In my research population it is possible that several items can appear several times, measured on different moments in time. This is being supplied in a total list with all observations identified by a number (per item) and a moment of observation (date). Now I want to make a unique list of this observation preserving the characteristics of the first observation. As example: Tree disease date Tree1 leaves 01-01-2009 Tree2 roots 13-09-2009 Tree1 roots 24-10-2009 Now I want to create a list of unique elements (in the example only once Tree1 and Tree2) with the first observed disease and date. For the example the result would look like: Tree disease date Tree1 roots 24-10-2008 Tree2 roots 13-09-2009 Can someone help me with this question? I think the function you will need include: ?as.Date #to get the date field into sortable form ?order#as in treedat2 <- treedat[ order(treedat$dt, treedat$Tree), ] ?duplicated # as in treedat2[ !duplicated(treedat2(Tree), ] -- David Winsemius, MD Heritage Laboratories West Hartford, CT __ 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 and provide commented, minimal, self-contained, reproducible code.
Re: [R] Unique observations
shouldn't the first observation for Tree1 be " Tree1 leaves 01-01-2009"?
> x <- read.table(textConnection("Tree disease date
+ Tree1 leaves 01-01-2009
+ Tree2 roots 13-09-2009
+ Tree1 roots 24-10-2009"), header=TRUE)
> closeAllConnections()
> # split by "Tree" and take first observation
> do.call('rbind', lapply(split(x, x$Tree), function(.tr) .tr[1,]))
Tree disease date
Tree1 Tree1 leaves 01-01-2009
Tree2 Tree2 roots 13-09-2009
>
On Wed, Nov 25, 2009 at 9:44 AM, John Lipkins
wrote:
> Hey R list,
>
> A beginners question. How can I do the following:
>
> In my research population it is possible that several items can appear
> several times, measured on different moments in time. This is being supplied
> in a total list with all observations identified by a number (per item) and
> a moment of observation (date). Now I want to make a unique list of this
> observation preserving the characteristics of the first observation. As
> example:
>
> Tree disease date
> Tree1 leaves 01-01-2009
> Tree2 roots 13-09-2009
> Tree1 roots 24-10-2009
>
> Now I want to create a list of unique elements (in the example only once
> Tree1 and Tree2) with the first observed disease and date. For the example
> the result would look like:
>
> Tree disease date
> Tree1 roots 24-10-2008
> Tree2 roots 13-09-2009
>
> Can someone help me with this question?
>
> Thanks in advance.
> Kind regards,
>
> John
>
> [[alternative HTML version deleted]]
>
> __
> 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
> 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?
__
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
and provide commented, minimal, self-contained, reproducible code.
[R] Unique observations
Hey R list, A beginners question. How can I do the following: In my research population it is possible that several items can appear several times, measured on different moments in time. This is being supplied in a total list with all observations identified by a number (per item) and a moment of observation (date). Now I want to make a unique list of this observation preserving the characteristics of the first observation. As example: Tree disease date Tree1 leaves 01-01-2009 Tree2 roots 13-09-2009 Tree1 roots 24-10-2009 Now I want to create a list of unique elements (in the example only once Tree1 and Tree2) with the first observed disease and date. For the example the result would look like: Tree disease date Tree1 roots 24-10-2008 Tree2 roots 13-09-2009 Can someone help me with this question? Thanks in advance. Kind regards, John [[alternative HTML version deleted]] __ 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 and provide commented, minimal, self-contained, reproducible code.
