Hi Another option is sapply/split/sum construction
with(data, sapply(split(x, ID), function(x) sum(x==0))) Regards Petr > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > project.org] On Behalf Of Carlos Nasher > Sent: Thursday, October 31, 2013 6:46 PM > To: S Ellison > Cc: r-help@r-project.org > Subject: Re: [R] Count number of consecutive zeros by group > > If I apply your function to my test data: > > ID <- c(1,1,1,2,2,3,3,3,3) > x <- c(1,0,0,0,0,1,1,0,1) > data <- data.frame(ID=ID,x=x) > rm(ID,x) > > f2 <- function(x) { > max( rle(x == 0)$lengths ) > } > with(data, tapply(x, ID, f2)) > > the result is > 1 2 3 > 2 2 2 > > which is not what I'm aiming for. It should be > 1 2 3 > 2 2 1 > > I think f2 does not return the max of consecutive zeros, but the max of > any consecutve number... Any idea how to fix this? > > > 2013/10/31 S Ellison <s.elli...@lgcgroup.com> > > > > > > > > -----Original Message----- > > > So I want to get the max number of consecutive zeros of variable x > > > for > > each > > > ID. I found rle() to be helpful for this task; so I did: > > > > > > FUN <- function(x) { > > > rles <- rle(x == 0) > > > } > > > consec <- lapply(split(df[,2],df[,1]), FUN) > > > > You're probably better off with tapply and a function that returns > > what you want. You're probably also better off with a data frame name > > that isn't a function name, so I'll use dfr instead of df... > > > > dfr<- data.frame(x=rpois(500, 1.5), ID=gl(5,100)) #5 ID groups > > numbered 1-5, equal size but that doesn't matter for tapply > > > > f2 <- function(x) { > > max( rle(x == 0)$lengths ) > > } > > with(dfr, tapply(x, ID, f2)) > > > > > > S Ellison > > > > > > ******************************************************************* > > This email and any attachments are confidential. Any > > u...{{dropped:24}} > > ______________________________________________ > 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.
