[R] Find each time a value changes
Tim Clark
mudiver1200 at yahoo.com
Thu Feb 11 02:58:40 CET 2010
Dear List,
I am trying to find each time a value changes in a dataset. The numbers are variables for day vs. night values, so what I am really getting is the daily sunrise and sunset.
A simplified example is the following:
x<-seq(1:100)
y1<-rep(1,10)
y2<-rep(2,10)
y<-c(y1,y2,y1,y1,y1,y2,y1,y2,y1,y2)
xy<-cbind(x,y)
I would like to know each time the numbers change.
Correct answer should be:
x=1,11,21,51,61,71,81,91
I would appreciate any help or suggestions. It seems like it should be simple but I’m stuck!
Thanks,
Tim
Tim Clark
Department of Zoology
University of Hawaii
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