Dear List, I have a data frame of data taken every few seconds. I would like to subset the data to retain only the data taken on the quarter hour, and as close to the quarter hour as possible. So far I have figured out how to subset the data to the quarter hour, but not how to keep only the minimum time for each quarter hour.
For example: mytime<-c("12:00:00","12:00:05","12:15:05","12:15:06","12:20:00","12:30:01","12:45:01","13:00:00","13:15:02") subtime<-grep(pattern="[[:digit:]]+[[:punct:]]00[[:punct:]][[:digit:]]+|[[:digit:]]+[[:punct:]]15[[:punct:]][[:digit:]]+|[[:digit:]]+[[:punct:]]30[[:punct:]][[:digit:]]+|[[:digit:]]+[[:punct:]]45[[:punct:]][[:digit:]]+",mytime) mytime[subtime] [1] "12:00:00" "12:00:05" "12:15:05" "12:15:06" "12:30:01" "12:45:01" "13:00:00" "13:15:02" This gives me the data taken at quarter hour intervals (removes 12:20:00) but I am still left with multiple values at the quarter hours. I would like to obtain: "12:00:00" "12:15:05" "12:30:01" "12:45:01" "13:00:00" "13:15:02" Thanks! Tim Tim Clark Department of Zoology University of Hawaii ______________________________________________ R-help@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.