[R] back tick names with predict function

[peter dalgaard]

Also, and possibly more constructively, when you get an error like
 
> CI.c = predict(mod2, data.frame( `plant-density` = x), interval = 'c')  # fail
Error in eval(predvars, data, env) : object 'plant-density' not found

you should check your assumptions. Does "newdata" actually contain a columnn called "plant-density":

> head(data.frame( `plant-density` = x))
  plant.density
1      65.00000
2      65.11912
3      65.23824
4      65.35736
5      65.47648
6      65.59560
> 

I.e., it doesn't. So check help for data.frame and looking for something with names.

> On 1 Dec 2023, at 01:47 , Bert Gunter <bgunter.4567 using gmail.com> wrote:
> 
> "Thank you Rui.  I didn't know about the check.names = FALSE argument.
>> Another good reminder to always read help, but I'm not sure I understood
>> what help to read in this case"
> 
> ?data.frame , of course, which says:
> 
> "check.names
> 
> logical. If TRUE then the names of the variables in the data frame are
> checked to ensure that they are syntactically valid variable names and
> are not duplicated. If necessary they are adjusted (by make.names) so
> that they are. "
> 
> -- Bert
> 
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-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Office: A 4.23
Email: pd.mes using cbs.dk  Priv: PDalgd using gmail.com