[R] Filter according to the latest data

[arun]

Hi,
Perhaps, (#Untested)
do.call(rbind,lapply(split(dat1,dat1$No),function(x) tail(x,1)))

#or
library(plyr)
ddply(dat1,.(No), function(x) x[nrow(x),])

A.K.


----- Original Message -----
From: Mat <matthias.weber at fnt.de>
To: r-help at r-project.org
Cc: 
Sent: Friday, February 1, 2013 3:04 AM
Subject: [R] Filter according to the latest data

Hello together,

i have a data.frame, like this one:
                 No.          Change           Date          
A              123           final                2013-01-15
B              123           error               2013-01-16
C              123           bug fixed       2013-01-17
D              111           final                2013-01-12

and now a want a new data.frame which includes only the newest entry for
each number.
The solution look like this:
                 No.          Change           Date          
C              123           bug fixed       2013-01-17
D              111           final                2013-01-12

is there any way to filter my data.frame to the latest data, perhabs "max"?

Thanks.

Mat



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