I'm having some trouble with Anova() in package "car". When the
model
formula is explicitly expressed:
library('nlme')
library('car')
fm <- lme(distance ~ age + Sex, data = Orthodont, random = ~ 1)
Anova() works fine:
Anova(fm)
However, if the model formula is scanned from an external source:
myModel <- as.formula("distance ~ age + Sex")
fm2 <- lme(myModel, data = Orthodont, random = ~ 1)
I get the following error:
Anova(fm2)
Error: object of type 'symbol' is not subsettable
How to resolve the situation when the model formula is defined externally?
Thanks,
Gang
Dear Gang,
The problem was in the model.matrix.lme() method provided by the car
package, and is now fixed in the development version of the car package on
R-Forge. You should be able to install it from there via
install.packages("car",
repos="http://R-Forge.R-project.org") after the
package is next built on R-Forge, usually in a day or so.
Best,
John
> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Gang
Chen
> Sent: January-13-15 1:48 PM
> To: r-help
> Subject: [R] Problem with Anova() in package "car"
>
> I'm having some trouble with Anova() in package "car". When
the model
> formula is explicitly expressed:
>
> library('nlme')
> library('car')
> fm <- lme(distance ~ age + Sex, data = Orthodont, random = ~ 1)
>
> Anova() works fine:
>
> Anova(fm)
>
> However, if the model formula is scanned from an external source:
>
> myModel <- as.formula("distance ~ age + Sex")
> fm2 <- lme(myModel, data = Orthodont, random = ~ 1)
>
> I get the following error:
>
> Anova(fm2)
> Error: object of type 'symbol' is not subsettable
>
> How to resolve the situation when the model formula is defined externally?
>
> Thanks,
> Gang
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
---
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Dear John, Thanks a lot for the quick response and fix! I'm looking forward to try out the development version. I assume that the fix will be released in the official version at some point. Thanks again, Gang On Tue, Jan 13, 2015 at 5:06 PM, John Fox <jfox at mcmaster.ca> wrote:> Dear Gang, > > The problem was in the model.matrix.lme() method provided by the car > package, and is now fixed in the development version of the car package on > R-Forge. You should be able to install it from there via > install.packages("car", repos="http://R-Forge.R-project.org") after the > package is next built on R-Forge, usually in a day or so. > > Best, > John > >> -----Original Message----- >> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Gang Chen >> Sent: January-13-15 1:48 PM >> To: r-help >> Subject: [R] Problem with Anova() in package "car" >> >> I'm having some trouble with Anova() in package "car". When the model >> formula is explicitly expressed: >> >> library('nlme') >> library('car') >> fm <- lme(distance ~ age + Sex, data = Orthodont, random = ~ 1) >> >> Anova() works fine: >> >> Anova(fm) >> >> However, if the model formula is scanned from an external source: >> >> myModel <- as.formula("distance ~ age + Sex") >> fm2 <- lme(myModel, data = Orthodont, random = ~ 1) >> >> I get the following error: >> >> Anova(fm2) >> Error: object of type 'symbol' is not subsettable >> >> How to resolve the situation when the model formula is defined externally? >> >> Thanks, >> Gang >> >> ______________________________________________ >> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see >> 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. > > > --- > This email has been checked for viruses by Avast antivirus software. > http://www.avast.com >