Detecting duplicate values
On Thu, 14 Aug 2008, Steven McKinney wrote:
-----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
Caveat: length(unique( c(1, NA ))) [1] 2
which may not be what Kevin wants. Alternatives: length( na.omit( unique( c(1, NA ) )) ) == 1 !isTRUE( any( a[1] != a[-1] ) HTH, Chuck
Steve McKinney
Thank you. Kevin
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