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stuck with repeated values
2 messages · SOUVIK BANDYOPADHYAY, Chuck Cleland
On 12/3/2008 6:32 AM, SOUVIK BANDYOPADHYAY wrote:
R Gurus,I have a vector of nearly 90,000 characters from which I have to
extract the index of the characters which are repeated. So suppose if
x<-c("a","a","b","a","b","c","d") then my output would be a vector having
the index where the values are repeated i.e (1,2,3,4,5). I have been able to
isolate out the values that are repeated from the unique list of characters
in x (i.e. y<-c("a","b")). One method can be to use a loop on the which
function but that would be too time consuming. Any hint on using the apply
function effectively would be useful
Thanks and Regards
x <- c("a","a","b","a","b","c","d")
duplicated(x)
[1] FALSE TRUE FALSE TRUE TRUE FALSE FALSE
x %in% x[duplicated(x)]
[1] TRUE TRUE TRUE TRUE TRUE FALSE FALSE
which(x %in% x[duplicated(x)])
[1] 1 2 3 4 5
?duplicated
Souvik Bandyopadhyay Lecturer, Dept of Biostatistics, Indian Institute of Public Health, Hyderabad [[alternative HTML version deleted]]
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Chuck Cleland, Ph.D. NDRI, Inc. (www.ndri.org) 71 West 23rd Street, 8th floor New York, NY 10010 tel: (212) 845-4495 (Tu, Th) tel: (732) 512-0171 (M, W, F) fax: (917) 438-0894