Message-ID: <4B01B330.40306@ucalgary.ca>
Date: 2009-11-16T20:16:48Z
From: Peter Ehlers
Subject: extracting the last row of each group in a data frame
In-Reply-To: <6e9bb1ed91068f2ef02f2b705c0fd05f.squirrel@webmail.andrew.cmu.edu>
I would use pkg:plyr, but just to show how
versatile R is:
ind <- cumsum(rle(as.numeric(dat$Name))$lengths)
dat[ind, ]
where I'm assuming that your data frame is
called 'dat'.
-Peter Ehlers
Hao Cen wrote:
> Hi,
>
> I would like to extract the last row of each group in a data frame.
>
> The data frame is as follows
>
> Name Value
> A 1
> A 2
> A 3
> B 4
> B 8
> C 2
> D 3
>
> I would like to get a data frame as
> Name Value
> A 3
> B 8
> C 2
> D 3
>
> Thank you for your suggestions in advance
>
> Jeff
>
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