Re: [R] Subsetting to unique values

From: jim holtman <jholtman_at_gmail.com>
Date: Fri, 06 Jun 2008 13:43:27 -0400

The interesting thing about R is that there are several ways to "skin the cat"; here is yet another solution:

> do.call(rbind, by(ddTable, ddTable$Id, function(z) z[1,,drop=FALSE]))
  Id name
1 1 Paul
2 2 Bob
>

On Fri, Jun 6, 2008 at 9:35 AM, Emslie, Paul [Ctr] <emsliep_at_atac.mil> wrote:

> I want to take the first row of each unique ID value from a data frame.
> For instance
> > ddTable <-
> data.frame(Id=c(1,1,2,2),name=c("Paul","Joe","Bob","Larry"))
>
> I want a dataset that is
> Id Name
> 1 Paul
> 2 Bob
>
> > unique(ddTable)
> Will give me all 4 rows, and
> > unique(ddTable$Id)
> Will give me c(1,2), but not accompanied by the name column.
>
> ______________________________________________
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html<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 you are trying to solve?

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Received on Fri 06 Jun 2008 - 18:05:28 GMT

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