Not quite, I need it like this, a new number for each ordered year in the sequence within each site, regardless of what the years are, and to retain the RchID column.
RchID site year index 1 A 2002 1 2 A 2004 2 3 A 2005 3 4 B 2003 1 5 B 2006 2 6 B 2008 3 7 C 2002 1 8 C 2003 2 9 C 2004 3 Thanks so much for you help! -----Original Message----- From: William Dunlap [mailto:wdun...@tibco.com] Sent: Tuesday, October 30, 2012 1:07 PM To: Meredith, Christy S -FS; r-help@R-project.org Subject: RE: [R] help with for loop: new column giving count of observation for each SITEID Is this what you want? > withinGroupIndex <- function(group, ...) ave(integer(length(group)), group, ..., FUN=seq_along) > site <- c("A","A","C","D","C","A","B") > data.frame(site, index=withinGroupIndex(site)) site index 1 A 1 2 A 2 3 C 1 4 D 1 5 C 2 6 A 3 7 B 1 You can add more arguments if the groups depend on more than one value: > year <- rep(c(1985, 2012), c(4,3)) > data.frame(site, year, index=withinGroupIndex(site, year)) site year index 1 A 1985 1 2 A 1985 2 3 C 1985 1 4 D 1985 1 5 C 2012 1 6 A 2012 1 7 B 2012 1 Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com > -----Original Message----- > From: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] On Behalf Of Meredith, Christy S > -FS > Sent: Tuesday, October 30, 2012 11:17 AM > To: r-help@R-project.org > Subject: [R] help with for loop: new column giving count of > observation for each SITEID > > > Hello, > I think this is easy, but I can't seem to find a good way to do this > in the R help. I have a list of sites, with multiple years of data for > each site id. I want to create a new column that gives a number > describing whether it is the 1st year ("1" ) the data was collected > for the site, the second year ("2"), etc. I have different years for > each siteid, but I don't care which year it was collected, just the order > that it is in for that siteid. This is what I have so far, but it doesn't do > the analysis separately for each SiteID. > > indexi<-indexg[order(indexg$SiteID,indexg$Yr),] > > obs=0 > indexi=na.omit(indexi) > for(i in 1:length(indexi$SiteID)){ > obs=obs+1 > indexi$obs[i]=obs > } > > > Thanks for any help you can give. > > Christy Meredith > USDA Forest Service > Rocky Mountain Research Station > PIBO Monitoring > Data Analyst > Voice: 435-755-3573 > Fax: 435-755-3563 > > > > > > This electronic message contains information generated by the USDA > solely for the intended recipients. Any unauthorized interception of > this message or the use or disclosure of the information it contains > may violate the law and subject the violator to civil or criminal > penalties. If you believe you have received this message in error, please > notify the sender and delete the email immediately. > > [[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.
