Re: [R] How to delete a duplicate observation

From: Greg Snow <Greg.Snow_at_intermountainmail.org>
Date: Thu, 13 Sep 2007 12:58:37 -0600

How about (assuming the data is in the data frame my.df):

> my.df2 <- my.df[order(my.df$V3, decreasing=TRUE),]
> my.df3 <- my.df2[ !duplicated( my.df2[,c('V1','V2')] ), ]

If order of the rows matters then we will need to add a couple of steps to reorder. You did not say what to do if 3 or more points matched, this approach takes the largest single V3 value from all matching on V1 and V2.

Hope this helps,

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow_at_intermountainmail.org
(801) 408-8111
 
 


> -----Original Message-----
> From: r-help-bounces_at_r-project.org
> [mailto:r-help-bounces_at_r-project.org] On Behalf Of nuyaying
> Sent: Thursday, September 13, 2007 10:51 AM
> To: r-help_at_stat.math.ethz.ch
> Subject: [R] How to delete a duplicate observation
>
>
>
> I have a data set with 3 variables V1, V2, V3. If there are
> 2 data points have the same values on both V1 and V2, I want
> to delete one of them which
> has smaller V3 value. i.e., in the data below, I want to delete
> the first observation. How can I do that ? Thanks in
> advance!
>
> V1 V2 V3
> 3 3 1
> 3 3 4
>
> --
> View this message in context:
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> 4437033.html#a12659033
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______________________________________________ R-help_at_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.
Received on Thu 13 Sep 2007 - 19:03:28 GMT

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