Hi Bill Many thanks for your help.
Cheers R -----Original Message----- From: William Dunlap [mailto:wdun...@tibco.com] Sent: 10 July 2012 17:22 To: Raghuraman Ramachandran; r-help@r-project.org Subject: RE: Help with vectors and rollapply It looks like you already have the zoo package loaded so you can use its na.locf(), which replaces NA's with the last non-NA value. Convert the 0s to NAs with replace() and feed the result into na.locf(): a <- c(-2,0,0,0,1,0,0,3,0,0,-4) aOut <- c(-2,-2,-2,-2,1,1,1,3,3,3,-4) na.locf(replace(a, a==0, NA) ) # [1] -2 -2 -2 -2 1 1 1 3 3 3 -4 all.equal(aOut, .Last.value) # [1] TRUE If you need to treat NA and 0 differently you will need to do more work. 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 Raghuraman > Ramachandran > Sent: Tuesday, July 10, 2012 8:23 AM > To: r-help@r-project.org > Subject: [R] Help with vectors and rollapply > > Hello > > I have a vector a =(-2,0,0,0,1,0,0,3,0,0,-4) > > I want to replace all zeros into previous non-zero state. So for > instance the above vector should be converted into: > > a= (-2,-2,-2,-2,1,1,1,3,3,3,-4) > > I tried many things and finally concluded that probably(?) rollapply > may be the best way? > > I tried > f= function(x){ > ifelse(x==0,Lag(x),x) > } > > And then, rollappy(a,1,f) and that didn't work. Can someone help please? > > Thx > R > > > Jefferies archives and monitors outgoing and incoming e-mail. The > contents of this email, including any attachments, are confidential to > the ordinary user of the email address to which it was addressed. 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If you received this transmission in error, please immediately contact the sender and destroy the material in its entirety, whether in electronic or hard copy format. Thank you. ______________________________________________ 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.
