[R] Applying function to all elements of a formula

[Dimitris Rizopoulos]

maybe another way is by reconstructing the formula using paste(), e.g.,

data <- data.frame(y = rnorm(5), x1 = runif(5),
     z = runif(5), age = runif(5))

nameRsp <- "y"
nams <- names(data)
namsX <- nams[!nams %in% nameRsp]
form <- as.formula(paste(nameRsp, "~" ,
     paste("log(", namsX, ")", sep = "", collapse = "+")))

lm(form, data)


I hope it helps.

Best,
Dimitris


On 6/18/2011 10:41 AM, Dennis Murphy wrote:
> Yes, it's possible, but if you want to do prediction on future
> x-values, you will likely have a problem.
>
> One way to do it would be something like (assuming y is the first column of dat)
>
> reg<- lm(y ~ log(as.matrix(dat[, -1])), dat)
>
> but the output would be pretty ugly (see summary(reg)). Another would
> be to construct the matrix outside the data frame and do something
> like
>
> X<- log(as.matrix(dat[, -1]))
> reg<- lm(dat$y ~ X)
>
> There may be better ways, though...
>
> Dennis
>
> On Fri, Jun 17, 2011 at 11:08 PM, Scott Fortmann-Roe<scottfr at gmail.com>  wrote:
>> Hi,
>>
>> I would like to do a regression like:
>>
>>          reg<- lm(y~log(.), data)
>>
>> where the log function is applied to "." in the form:
>>
>>         log(x1)+ log(x2)+ log(x3)...
>>
>> instead of in the form
>>
>>        log(x1+x2+x3+...)
>>
>>
>> Is this possible?
>>
>> Thank you,
>> Scott
>>
>>         [[alternative HTML version deleted]]
>>
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>>
>
> ______________________________________________
> R-help at r-project.org mailing list
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

-- 
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center

Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
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