[R] Error in model.frame.default

[David Winsemius]

On Mar 4, 2011, at 4:47 AM, Heike Schmitz wrote:

> Hi again, dear Dennis,
>
> i checked the spelling in Zuur et al. and they wrote it like i did.
> I tried your suggestion but now i have another warning message:
>
>
>> D1<- data.frame(L.AREA= Loyn$L.AREA[Loyn$fGRAZE==1], fGraze = "1")
>
> Error in data.frame(L.AREA = Loyn$L.AREA[Loyn$fGRAZE == 1], fGraze =  
> "1") :
>   arguments imply differing number of rows: 0, 1

In the code you originally offered, 'fGRAZE' was just a vector in the  
global environment and not in the 'Lon' dataframe.

-- 
David.

>
> My aim i to display the predicted/fitted values of the different  
> slopes
> for a  factor in a plot.
> I tried different ways for my own data and when i found this  
> solution i
> was happy, but even the provided solution with the provided dataset do
> not work...
> aaaahhhhh.
>
> Any ideas?? First i thought i had a problem with missing values, but  
> in
> the Zuur data are no missing values.
>
> Heike
>
>
>
> Am 3/3/2011 18:51, schrieb Dennis Murphy:
>> Hi:
>>
>> You need the second variable in D1 to be named fGRAZE - the variable
>> names in the newdata data frame (D1) have to be the same as the
>> variable names on the RHS of the model formula, in this case L.AREA
>> and fGRAZE.
>>
>> HTH,
>> Dennis
>>
>> On Thu, Mar 3, 2011 at 7:43 AM, Heike Schmitz <schmitzh at uni-bremen.de
>> <mailto:schmitzh at uni-bremen.de>> wrote:
>>
>>    Dear R- Community,
>>
>>    to learn i reanalysed some data provided and analysed by Zuur et.
>>    al. in their book "Mixed effect models and Extensions in Ecology
>>    with R". When i run the last command i get a warning message i
>>    dont understand.
>>
>>
>>    Loyn<- read.table(file = "loyn.txt",header = TRUE)
>>    Loyn$L.AREA<- log10(Loyn$AREA)
>>    fGRAZE <-factor(Loyn$GRAZE)
>>
>>    M0<- lm(ABUND~ L.AREA + fGRAZE, data = Loyn)
>>    summary(M0)
>>
>>    plot(x = Loyn$L.AREA, y = Loyn$ABUND,
>>       xlab = "Log transformed AREA",
>>       ylab = "Bird Abundance")
>>
>>    D1<- data.frame(L.AREA= Loyn$L.AREA[Loyn$GRAZE==1], fGraze = "1")
>>    P1<- predict(M0,newdata = D1)
>>
>>    Warning message:
>>    Error in model.frame.default(Terms, newdata, na.action =
>>    na.action, xlev = object$xlevels) :
>>     variable lengths differ (found for 'fGRAZE')
>>    In addition: Warning message:
>>    'newdata' had 13 rows but variable(s) found have 56 rows
>>
>>    I hope anyone has an idea.
>>    Thank you in advance.
>>    Heike
>>
>>    --
>>    Heike Schmitz- Diaspero
>>    Population Ecology and Evolutionary Ecology Lab, FB2
>>    University of Bremen
>>    Leobener Strasse, Nw2, Room B4050
>>    D-28359 Bremen
>>    Germany
>>    fon ++49-421-218-62937
>>    email: heike.schmitz at uni-bremen.de
>>    <mailto:heike.schmitz at uni-bremen.de>
>>
>>    http://www.popecol.uni-bremen.de
>>
>>    ______________________________________________
>>    R-help at r-project.org <mailto: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.
>>
>>
>
> -- 
> Heike Schmitz- Diaspero
> Population Ecology and Evolutionary Ecology Lab, FB2
> University of Bremen
> Leobener Strasse, Nw2, Room B4050
> D-28359 Bremen
> Germany
> fon ++49-421-218-62937
> email: heike.schmitz at uni-bremen.de
>
> http://www.popecol.uni-bremen.de
>
>
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>
> ______________________________________________
> 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.

David Winsemius, MD
Heritage Laboratories
West Hartford, CT