Now it works I was reading from a file DF <- read.table("prueba.txt") DF[!as.POSIXlt(DF$V1)[['min']] %% 10,] didn't do anything, then I tried zz[!as.POSIXlt(zz$V2)[['min']] %% 10,] that caused an error Error en as.POSIXlt.character(as.character(x)) : character string is not in a standard unambiguous format
what if you use zoo and chron instead? I say that because I'd like to make more computation later with zoo. and what I relly need is to keep the last data in each 15min piece. Giving it a 15min time format commonly I'll have one data every 5 min, but sometimes some could be missing or not be a 5min multiple. 2005-01-03 09:04 0.01 -> ignore because the next one is nearer to 15 2005-01-03 09:05 0.02 -> 2005-01-03 09:15 0.02 2005-01-03 09:24 0.03 -> 2005-01-03 09:30 0.03 -- View this message in context: http://r.789695.n4.nabble.com/remove-rows-tp2328312p2328517.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.