Also,
it might be faster to use ?data.table() library(data.table) dt1<- data.table(dat1,key='id.name') dt1[,x:=seq(.N),by='id.name'] A.K. On , arun <smartpink...@yahoo.com> wrote: Hi, Try: dat1<- structure(list(id.name = c(123.45, 123.45, 123.45, 123.45, 234.56, 234.56, 234.56, 234.56, 234.56, 234.56, 234.56, 345.67, 345.67, 345.67, 456.78, 456.78, 456.78, 456.78, 456.78, 456.78, 456.78, 456.78, 456.78)), .Names = "id.name", class = "data.frame", row.names = c(NA, -23L)) dat1$x <- with(dat1,ave(id.name,id.name,FUN=seq)) A.K. On Friday, October 11, 2013 9:28 AM, Steven Ranney <steven.ran...@gmail.com> wrote: Hello all - I have an example column in a dataFrame id.name 123.45 123.45 123.45 123.45 234.56 234.56 234.56 234.56 234.56 234.56 234.56 345.67 345.67 345.67 456.78 456.78 456.78 456.78 456.78 456.78 456.78 456.78 456.78 ... [truncated] And I'd like to create a second vector of sequential values (i.e., 1:N) for each unique id.name value. In other words, I need id.name x 123.45 1 123.45 2 123.45 3 123.45 4 234.56 1 234.56 2 234.56 3 234.56 4 234.56 5 234.56 6 234.56 7 345.67 1 345.67 2 345.67 3 456.78 1 456.78 2 456.78 3 456.78 4 456.78 5 456.78 6 456.78 7 456.78 8 456.78 9 The number of unique id.name values is different; for some values, nrow() may be 42 and for others it may be 36, etc. The only way I could think of to do this is with two nested for loops. I tried it but because this data set is so large (nrow = 112,679 with 2,161 unique values of id.name), it took several hours to run. Is there an easier way to create this vector? I'd appreciate your thoughts. Thanks - SR Steven H. Ranney [[alternative HTML version deleted]] ______________________________________________ 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. ______________________________________________ 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.
