[R] extracting the last row of each group in a data frame

[Hao Cen]

Thanks to all who helped. These are all great suggestions. 

Jeff

-----Original Message-----
From: Gabor Grothendieck [mailto:ggrothendieck at gmail.com] 
Sent: Monday, November 16, 2009 6:27 PM
To: Hao Cen
Cc: r-help at r-project.org
Subject: Re: [R] extracting the last row of each group in a data frame

Try this:

> aggregate(DF[-1], DF[1], tail, 1)
  Name Value
1    A     3
2    B     8
3    C     2
4    D     3


On Mon, Nov 16, 2009 at 2:42 PM, Hao Cen <hcen at andrew.cmu.edu> 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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