I have a dataset which contains some missing values, and I need to replace
them with zeros. I tried using the following:
x <- matrix(data=rep(c(1,2,3,NA),6), ncol=6, nrow=6)
y <- matrix(data=0, ncol=ncol(x), nrow=nrow(x))
for(i in 1:nrow(x)) {
for(j in 1:ncol(x)) {
y[i,j] <- ifelse(x[i,j]==NA, 0, x[i,j])
}}
But y returns an NA matrix.
I'd appreciate any help.
--
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Hello rafamoral, Try this: ifelse(is.na(x),0,x) On Wed, Jan 14, 2009 at 8:32 PM, rafamoral <rafa_moral2004 at yahoo.com.br> wrote:> > I have a dataset which contains some missing values, and I need to replace > them with zeros. I tried using the following: > > x <- matrix(data=rep(c(1,2,3,NA),6), ncol=6, nrow=6) > > y <- matrix(data=0, ncol=ncol(x), nrow=nrow(x)) > > for(i in 1:nrow(x)) { > > for(j in 1:ncol(x)) { > > y[i,j] <- ifelse(x[i,j]==NA, 0, x[i,j]) > > }} > > But y returns an NA matrix. > I'd appreciate any help. > -- > View this message in context: http://www.nabble.com/Logical-function-to-turn-missing-values-to-0%27s-tp21466785p21466785.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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 rafamoral, Try this: x[is.na(x)]<-0 HTH, Jorge On Wed, Jan 14, 2009 at 5:32 PM, rafamoral <rafa_moral2004@yahoo.com.br>wrote:> > I have a dataset which contains some missing values, and I need to replace > them with zeros. I tried using the following: > > x <- matrix(data=rep(c(1,2,3,NA),6), ncol=6, nrow=6) > > y <- matrix(data=0, ncol=ncol(x), nrow=nrow(x)) > > for(i in 1:nrow(x)) { > > for(j in 1:ncol(x)) { > > y[i,j] <- ifelse(x[i,j]==NA, 0, x[i,j]) > > }} > > But y returns an NA matrix. > I'd appreciate any help. > -- > View this message in context: > http://www.nabble.com/Logical-function-to-turn-missing-values-to-0%27s-tp21466785p21466785.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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. >[[alternative HTML version deleted]]
ONKELINX, Thierry
2009-Jan-15 09:08 UTC
[R] Logical function to turn missing values to 0's
Use the is.na function to test for NA values. And do read about vectorizing your code. You don't need loops for this problem. Without loops your code will run more than 400 times faster!> n <- 1000 > x <- matrix(data=rep(c(1,2,3,NA), n), ncol=n, nrow=n) > > system.time({+ y <- matrix(data=0, ncol=ncol(x), nrow=nrow(x)) + for(i in 1:nrow(x)) { + for(j in 1:ncol(x)) { + y[i,j] <- ifelse(is.na(x[i,j]), 0, x[i,j]) + } + } + }) user system elapsed 45.17 0.30 45.61> system.time(y <- ifelse(is.na(x), 0, x))user system elapsed 0.60 0.15 0.75> system.time({+ y <- x + y[is.na(x)] <- 0 + }) user system elapsed 0.11 0.00 0.11 ------------------------------------------------------------------------ ---- ir. Thierry Onkelinx Instituut voor natuur- en bosonderzoek / Research Institute for Nature and Forest Cel biometrie, methodologie en kwaliteitszorg / Section biometrics, methodology and quality assurance Gaverstraat 4 9500 Geraardsbergen Belgium tel. + 32 54/436 185 Thierry.Onkelinx at inbo.be www.inbo.be To call in the statistician after the experiment is done may be no more than asking him to perform a post-mortem examination: he may be able to say what the experiment died of. ~ Sir Ronald Aylmer Fisher The plural of anecdote is not data. ~ Roger Brinner The combination of some data and an aching desire for an answer does not ensure that a reasonable answer can be extracted from a given body of data. ~ John Tukey -----Oorspronkelijk bericht----- Van: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] Namens rafamoral Verzonden: woensdag 14 januari 2009 23:32 Aan: r-help at r-project.org Onderwerp: [R] Logical function to turn missing values to 0's I have a dataset which contains some missing values, and I need to replace them with zeros. I tried using the following: x <- matrix(data=rep(c(1,2,3,NA),6), ncol=6, nrow=6) y <- matrix(data=0, ncol=ncol(x), nrow=nrow(x)) for(i in 1:nrow(x)) { for(j in 1:ncol(x)) { y[i,j] <- ifelse(x[i,j]==NA, 0, x[i,j]) }} But y returns an NA matrix. I'd appreciate any help. -- View this message in context: http://www.nabble.com/Logical-function-to-turn-missing-values-to-0%27s-t p21466785p21466785.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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. Dit bericht en eventuele bijlagen geven enkel de visie van de schrijver weer en binden het INBO onder geen enkel beding, zolang dit bericht niet bevestigd is door een geldig ondertekend document. The views expressed in this message and any annex are purely those of the writer and may not be regarded as stating an official position of INBO, as long as the message is not confirmed by a duly signed document.