predict.lm with NAs

see ?na.exclude

you can set na.action='na.exclude' when fit the model.

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!

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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
http://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
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..(....)... 0ooo...                              Walmes Zeviani
...\..(.....(.....)...     Master in Statistics and Agricultural
Experimentation
....\_)..... )../....       walmeszeviani at hotmail.com, Lavras - MG, Brasil
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(_/............................................................................................

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