Dear members,
I have a series of values in a vector and some value are missing and
replaced with NA.
For example:
a <- c(27, 25, NA, NA, 24, 26, 27, NA, 26)
I would like to replace the NAs with the value taken from the previous
value that is non-NA. The output would be in this case:
27 25 25 25 24 26 27 27 26
Now I do that with a for loop, but I try to eliminate all the loops to
gain in performance
I try this and it works but again I have a while and then I do not
eliminate completely loop:
l <- length(a)
while(any(is.na(a))) {a[2:l] <- ifelse(is.na(a[2:l]), a[1:(l-1)], a[2:l])}
If someone have another solution, I will be most happy !
Sincerely
Marc Girondot
--
__________________________________________________________
Marc Girondot, Pr
Laboratoire Ecologie, Syst?matique et Evolution
Equipe de Conservation des Populations et des Communaut?s
CNRS, AgroParisTech et Universit? Paris-Sud 11 , UMR 8079
B?timent 362
91405 Orsay Cedex, France
Tel: 33 1 (0)1.69.15.72.30 Fax: 33 1 (0)1.69.15.73.53
e-mail: marc.girondot at u-psud.fr
Web: http://www.ese.u-psud.fr/epc/conservation/Marc.html
Skype: girondot
Take a look at na.locf() in the zoo package. (LOCF = last observation carried forward) RMW On Thu, Nov 22, 2012 at 12:56 PM, Marc Girondot <marc_grt at yahoo.fr> wrote:> Dear members, > > I have a series of values in a vector and some value are missing and > replaced with NA. > For example: > a <- c(27, 25, NA, NA, 24, 26, 27, NA, 26) > I would like to replace the NAs with the value taken from the previous value > that is non-NA. The output would be in this case: > > 27 25 25 25 24 26 27 27 26 > > Now I do that with a for loop, but I try to eliminate all the loops to gain > in performance > > I try this and it works but again I have a while and then I do not eliminate > completely loop: > > l <- length(a) > while(any(is.na(a))) {a[2:l] <- ifelse(is.na(a[2:l]), a[1:(l-1)], a[2:l])} > > If someone have another solution, I will be most happy ! > > Sincerely > > Marc Girondot > > -- > __________________________________________________________ > Marc Girondot, Pr > > Laboratoire Ecologie, Syst?matique et Evolution > Equipe de Conservation des Populations et des Communaut?s > CNRS, AgroParisTech et Universit? Paris-Sud 11 , UMR 8079 > B?timent 362 > 91405 Orsay Cedex, France > > Tel: 33 1 (0)1.69.15.72.30 Fax: 33 1 (0)1.69.15.73.53 > e-mail: marc.girondot at u-psud.fr > Web: http://www.ese.u-psud.fr/epc/conservation/Marc.html > Skype: girondot > > ______________________________________________ > R-help at 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.
Dear Marc, Try require(zoo) na.locf(a) HTH, Jorge.- On Thu, Nov 22, 2012 at 11:56 PM, Marc Girondot <> wrote:> Dear members, > > I have a series of values in a vector and some value are missing and > replaced with NA. > For example: > a <- c(27, 25, NA, NA, 24, 26, 27, NA, 26) > I would like to replace the NAs with the value taken from the previous > value that is non-NA. The output would be in this case: > > 27 25 25 25 24 26 27 27 26 > > Now I do that with a for loop, but I try to eliminate all the loops to > gain in performance > > I try this and it works but again I have a while and then I do not > eliminate completely loop: > > l <- length(a) > while(any(is.na(a))) {a[2:l] <- ifelse(is.na(a[2:l]), a[1:(l-1)], a[2:l])} > > If someone have another solution, I will be most happy ! > > Sincerely > > Marc Girondot > > -- > ______________________________**____________________________ > Marc Girondot, Pr > > Laboratoire Ecologie, Systématique et Evolution > Equipe de Conservation des Populations et des Communautés > CNRS, AgroParisTech et Université Paris-Sud 11 , UMR 8079 > Bâtiment 362 > 91405 Orsay Cedex, France > > Tel: 33 1 (0)1.69.15.72.30 Fax: 33 1 (0)1.69.15.73.53 > e-mail: marc.girondot@u-psud.fr > Web: http://www.ese.u-psud.fr/epc/**conservation/Marc.html<http://www.ese.u-psud.fr/epc/conservation/Marc.html> > Skype: girondot > > ______________________________**________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/**listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help> > PLEASE do read the posting guide http://www.R-project.org/** > posting-guide.html <http://www.R-project.org/posting-guide.html> > and provide commented, minimal, self-contained, reproducible code. >[[alternative HTML version deleted]]