[R] back tick names with predict function

[Robert Baer]

On 12/1/2023 11:47 AM, peter dalgaard wrote:
> 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":

Great advice/strategy. Thanks!


>> 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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