Re: [R] Subsetting to unique values

From: Chuck Cleland <ccleland_at_optonline.net>
Date: Fri, 06 Jun 2008 10:08:34 -0400

On 6/6/2008 9:35 AM, Emslie, Paul [Ctr] 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.

ddTable <- data.frame(Id=c(1,1,2,2),name=c("Paul","Joe","Bob","Larry"))

!duplicated(ddTable$Id)
[1] TRUE FALSE TRUE FALSE ddTable[!duplicated(ddTable$Id),]

   Id name
1 1 Paul
3 2 Bob

?duplicated

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-- 
Chuck Cleland, Ph.D.
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Received on Fri 06 Jun 2008 - 14:29:50 GMT

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