[R] Simple question on finding duplicates

[Bert Gunter]

ummm...
?duplicates

-- Bert

On Wed, Jul 25, 2012 at 1:22 PM, David L Carlson <dcarlson at tamu.edu> wrote:
> duplicate <- ifelse(c(0, a$col[-length(a$col)])==c(a$col), 1, 0)
>
> ----------------------------------------------
> David L Carlson
> Associate Professor of Anthropology
> Texas A&M University
> College Station, TX 77843-4352
>
>
>> -----Original Message-----
>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
>> project.org] On Behalf Of Jeff
>> Sent: Wednesday, July 25, 2012 3:06 PM
>> To: r-help at r-project.org
>> Subject: [R] Simple question on finding duplicates
>>
>>
>>    I'm  trying  to find duplicate values in a column of a data frame.
>> For
>>    example, dataframe (a) below has two 3's. I would like to mark each
>> value of
>>    each row as either not being a duplicate of the one before (0), or
>> as a
>>    duplicate (1) - for example, as in dataframe (b). In SPSS, I would
>> simply
>>    compare each value to it's "lagged" value, but I can't figure out
>> how to do
>>    this with R.
>>    Can someone point me in the right direction?
>>    Thanks
>>    a <- data.frame( col1 = c(1,2,3,3,4))
>>    b <- data.frame( col1 = c(1,2,3,3,4), duplicate = c(0,0,0,1,0))
>> ______________________________________________
>> R-help at r-project.org mailing list
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>> PLEASE do read the posting guide http://www.R-project.org/posting-
>> guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> 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.



-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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