Hi R, I have a dataframe with dim(test) [1] 435150 4 class(test) [1] "data.frame" In the third column every time a number with "-" appears I need to replace with previous value I am using the following code s=which(substr(as.character(test[,3]),1,1)=="-") for(i in 1:length(s)) test[s[i],3] = test[s[i]-1,3]
Is there a faster way of doing this? sessionInfo() R version 2.5.1 (2007-06-27) i386-pc-mingw32 locale: LC_COLLATE=English_United States.1252;LC_CTYPE=English_United States.1252;LC_MONETARY=English_United States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252 attached base packages: [1] "stats" "graphics" "grDevices" "utils" "datasets" "methods" [7] "base" Thanks in advance Ravi Shankar S This e-mail may contain confidential and/or privileged i...{{dropped:10}} ______________________________________________ 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.