Hi, I wanted to use the predict.lm() function to compare the empirical data with the predicted values. The problem is that I have NAs in my data. I wanted to cbind my data.frame with the empirical values with the vector I get from predict.lm. But they don't have the same length because predict.lm just skip NA-predictions. Is there a way to get a vector with predicted values of the same length as the empirical values (with NAs)? thanks!
see ?na.exclude you can set na.action='na.exclude' when fit the model. On 15 April 2010 09:06, Martin Batholdy <batholdy at googlemail.com> wrote:> Hi, > > I wanted to use the predict.lm() function to compare the empirical data with the predicted values. > The problem is that I have NAs in my data. > > I wanted to cbind my data.frame with the empirical values with the vector I get from predict.lm. > But they don't have the same length because predict.lm just skip NA-predictions. > > Is there a way to get a vector with predicted values of the same length as the empirical values (with NAs)? > > > thanks! > > ______________________________________________ > R-help at r-project.org mailing list > stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >-- Wincent Rong-gui HUANG Doctoral Candidate Dept of Public and Social Administration City University of Hong Kong asrr.r-forge.r-project.org/rghuang.html
You can use predict() by specifying a complete data.frame() for prediction to the argument newdata=. Look: da <- expand.grid(x1=LETTERS[1:4], x2=1:9) da$y <- rnorm(da$x1) da$y[sample(length(da$y), 5)] <- NA m0 <- lm(y~x1+x2, data=da) predict(m0) # NA not predicted predict(m0, newdata=da) # NA predicted Sincerely. Walmes. ----- ..ooo0 ................................................................................................... ..(....)... 0ooo... Walmes Zeviani ...\..(.....(.....)... Master in Statistics and Agricultural Experimentation ....\_)..... )../.... walmeszeviani at hotmail.com, Lavras - MG, Brasil ............ (_/............................................................................................ -- View this message in context: n4.nabble.com/predict-lm-with-NAs-tp1840661p1886457.html Sent from the R help mailing list archive at Nabble.com.