[R] Detecting duplicate values

[Steven McKinney]

> -----Original Message-----
> From: r-help-bounces at r-project.org
[mailto:r-help-bounces at r-project.org]
> On Behalf Of rkevinburton at charter.net
> Sent: Thursday, August 14, 2008 2:00 PM
> To: r-help at r-project.org
> Subject: [R] Detecting duplicate values
> 
> This is another "how do I do it" type of question. It seems that for a
> function that I have it has a hard time with lists that have a single
> repeated value. I want a function (or expression)  that will detect
this
> condition. I want to detect:
> 
> c(2,2,2,2,2)
> OR
> c(1)
> 
> The following is OK
> 
> c(2,3,3,2)
> OR
> c(1,2,1)
> 
> These lists are "OK" because they have another value in the list. In
other
> words I want to detect if there is only one element in the list that
> repeats 1 or more times.
> 
> Will length(table(a)) = 1 always work? If so I have answered my own
> question. If not please bear with me as I have missed a case.

Consider also 
length(unique(a)) == 1

Steve McKinney

> 
> Thank you.
> 
> Kevin
> 
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