[Rd] Evaluation without the parent frame

[Terry Therneau]

Duncan,
   I agree completely with "don't use attach"; if I could get all the 
users of the survival package to agree as well the problem in question 
would go away :-)  I'm thinking about ways to add more effective error 
surveillance.
   Your suggestion was not horribly complex and I'll look into it 
further.  My first foray failed because what I want (I think) is the 
environment that they had when the first ">" came up.  I tried baseenv 
in a spot, but then my code couldn't find the model.frame function.

Terry T.



On 05/17/2012 05:00 AM, Duncan wrote:
> On 12-05-16 4:59 PM, Terry Therneau wrote:
>> >  I've been tracking down a survival problem from R-help today.  A short
>> >  version of the primary issue is reconstructed by the following simple
>> >  example:
>> >
>> >  library(survival)
>> >  attach(lung)
>> >  fit<- coxph(Surv(time, status) ~ log(age))
>> >  predict(fit, newdata=data.frame(abe=45))
>> >
>> >  Note the typo in the last line of "abe" instead of "age".  Instead of an
>> >  error message, this returns predictions for all the subjects since
>> >  model.frame matches "age" by searching more widely.   I'd prefer the error.
>> >  I suspect this is hard -- I'd like it to not see the attached lung data
>> >  set, but still be able to find the log function.
>> >  Is there a not-horribly-complex solution?
> The best solution is to not use attach(), use data=lung in the fit.
>
> I think if you want to use attach but limit the search, you need
> something like
>
> predict(fit, newdata=list2env(data.frame(abe=45), parent=baseenv()))
>
> but I don't think that meets your "not horribly complex" criterion.
>
> Duncan Murdoch
>
>> >
>> >  I also tried to change the primary function to lm instead of coxph.  It
>> >  has the same problem, but does print a warning that the newdata and
>> >  results have different lengths (which I will incorporate).
>> >
>> >  Terry T.
>> >
>> >