Hi I think I have been struggling to use replace correctly, I usually work my way around this using a loop, but I think this is in fact inefficient.
I have a dataset with runoff from three plots and associated rainfall. However either the datarecording was sloppy, or the rainfall very patchy. So I am trying to remove data from my dataset for which the runoff is larger than the rainfall on the same day. (Don't worry, the rainfall data is in fact the rainfall associated to the three days around the runoff event). On days that no runoff was recorded the data includes "NA" The dataset is called wheat2 I use the following: for (i in 1:nrow(wheat2)) { # Insert NA's if runoff data > rainfall data if (is.na(wheat2[i,5:7])==FALSE && any(wheat2[i,5:7]>wheat2[i,8])) { wheat2[i,5:7] <- NA } } I tried this: wheat1 <- replace(wheat2[,5:7],is.na(wheat2[i,5:7])==FALSE && any(wheat2[i,5:7]>wheat2[i,8]),NA) wheat3 <- cbind(wheat2[1:4],wheat1,wheat2[,8]) > wheat3[5539,] # the culprit row DateRain Rain StartDate EndDate RO.A RO.B RO.C filtered.Rain 5539 28-Feb-58 0 27-Feb-58 28-Feb-58 61.5 88.7 65 0 Not sure what I am doing wrong, any help is appreciated Willem Here is a data sample and note the very high value for runoff (RO) and no rainfall on 28 Feb 1958 DateRain Rain StartDate EndDate RO.A RO.B RO.C filtered.Rain 14-Feb-58 0 NA NA NA 0 15-Feb-58 0 NA NA NA 0 16-Feb-58 0 NA NA NA 0 17-Feb-58 0 NA NA NA 0 18-Feb-58 0 18-Feb-58 18-Feb-58 0 0 0 23.6 19-Feb-58 23.6 NA NA NA 23.6 20-Feb-58 0 NA NA NA 23.6 21-Feb-58 0 NA NA NA 0 22-Feb-58 0 NA NA NA 0 23-Feb-58 0 NA NA NA 0 24-Feb-58 0 NA NA NA 0 25-Feb-58 0 NA NA NA 0 26-Feb-58 0 NA NA NA 0 27-Feb-58 0 NA NA NA 0 28-Feb-58 0 27-Feb-58 28-Feb-58 61.5 88.7 65 0 01-Mar-58 0 NA NA NA 0 02-Mar-58 0 NA NA NA 0 03-Mar-58 0 NA NA NA 0 04-Mar-58 0 NA NA NA 1.5 05-Mar-58 1.5 NA NA NA 1.5 06-Mar-58 0 NA NA NA 1.5 07-Mar-58 0 NA NA NA 0.5 08-Mar-58 0.5 NA NA NA 0.5 09-Mar-58 0 NA NA NA 7.6 10-Mar-58 7.1 NA NA NA 9.1 11-Mar-58 2 NA NA NA 57.4 12-Mar-58 48.3 09-Mar-58 12-Mar-58 0.1 1.5 0 51.1 13-Mar-58 0.8 NA NA NA 49.9 14-Mar-58 0.8 NA NA NA 1.6 ______________________________________________ R-help@stat.math.ethz.ch 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.