Re: [R] Question on passing the subset argument to an lm wrapper

2010-10-25 Thread Charles C. Berry 

On Sun, 24 Oct 2010, Erik Iverson wrote:


Hello,

How would you go about handling the following situation?
This is on R 2.12.0 on Ubuntu 32-bit.

I have a wrapper function to lm.  I want to pass in a
subset argument.  First, I just thought I'd use 


The subset arg needs to be unevaluated until lm() - or whatever function 
- is called in your function.


The canonical advice for this kind of question about passing unevaluated 
args is to study the first lines of the function lm noting what it does 
with objects cl - match.call() and mf - match.call( expand.dots = FALSE 
).


Something like this might be what you want:

testlm2 - function(formula, ...) {
mc - match.call()
mc[[1]] - as.name('lm')
eval(mc)
}

testlm2(bmi ~ age, data= df1, subset = age  50)

HTH,

Chuck




## make example reproducible
set.seed(123)
df1 - data.frame(age = rnorm(100, 50, 10),
  bmi = rnorm(100, 30, sd = 2))

## create a wrapper using ...
testlm - function(formula, ...) {
 lm(formula, data = df1, ...)
}


 testlm(bmi ~ age, subset = age  50)


Error in eval(expr, envir, enclos) :
  ..1 used in an incorrect context, no ... to look in

I found some other examples of this error message,
but couldn't piece together how it fits in with this
example.

Next, I tried specifying a subset argument.

testlm2 - function(formula, subset) {
 lm(formula, data = df1, subset = subset)
}


 testlm2(bmi ~ age, subset = age  50)


Error in xj[i] : invalid subscript type 'closure'

I also don't understand this one.

Any pointers on if I'm just missing the easy
solution to do what I want?  Any explanations
as to the above behavior (I know it has to do
with model.frame, but not sure how) would also
be greatly appreciated!

Thanks!
--Erik

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Charles C. Berry(858) 534-2098
Dept of Family/Preventive Medicine
E mailto:cbe...@tajo.ucsd.edu   UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego 92093-0901

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and provide commented, minimal, self-contained, reproducible code.

Re: [R] Question on passing the subset argument to an lm wrapper

2010-10-25 Thread Henrique Dallazuanna 
As workaround you can try this:

testlm - function(formula, ...) {
 args - list(formula, data = df1, ...)
 do.call(lm, args)
}

testlm(bmi ~ age, subset = df1$age  50)



On Mon, Oct 25, 2010 at 2:16 AM, Erik Iverson er...@ccbr.umn.edu wrote:

 Hello,

 How would you go about handling the following situation?
 This is on R 2.12.0 on Ubuntu 32-bit.

 I have a wrapper function to lm.  I want to pass in a
 subset argument.  First, I just thought I'd use 

 ## make example reproducible
 set.seed(123)
 df1 - data.frame(age = rnorm(100, 50, 10),
  bmi = rnorm(100, 30, sd = 2))

 ## create a wrapper using ...
 testlm - function(formula, ...) {
  lm(formula, data = df1, ...)
 }

  testlm(bmi ~ age, subset = age  50)

 Error in eval(expr, envir, enclos) :
  ..1 used in an incorrect context, no ... to look in

 I found some other examples of this error message,
 but couldn't piece together how it fits in with this
 example.

 Next, I tried specifying a subset argument.

 testlm2 - function(formula, subset) {
  lm(formula, data = df1, subset = subset)
 }

  testlm2(bmi ~ age, subset = age  50)

 Error in xj[i] : invalid subscript type 'closure'

 I also don't understand this one.

 Any pointers on if I'm just missing the easy
 solution to do what I want?  Any explanations
 as to the above behavior (I know it has to do
 with model.frame, but not sure how) would also
 be greatly appreciated!

 Thanks!
 --Erik

 __
 R-help@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.




-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40 S 49° 16' 22 O

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[R] Question on passing the subset argument to an lm wrapper

2010-10-24 Thread Erik Iverson 

Hello,

How would you go about handling the following situation?
This is on R 2.12.0 on Ubuntu 32-bit.

I have a wrapper function to lm.  I want to pass in a
subset argument.  First, I just thought I'd use 

## make example reproducible
set.seed(123)
df1 - data.frame(age = rnorm(100, 50, 10),
  bmi = rnorm(100, 30, sd = 2))

## create a wrapper using ...
testlm - function(formula, ...) {
  lm(formula, data = df1, ...)
}

 testlm(bmi ~ age, subset = age  50)

Error in eval(expr, envir, enclos) :
  ..1 used in an incorrect context, no ... to look in

I found some other examples of this error message,
but couldn't piece together how it fits in with this
example.

Next, I tried specifying a subset argument.

testlm2 - function(formula, subset) {
  lm(formula, data = df1, subset = subset)
}

 testlm2(bmi ~ age, subset = age  50)

Error in xj[i] : invalid subscript type 'closure'

I also don't understand this one.

Any pointers on if I'm just missing the easy
solution to do what I want?  Any explanations
as to the above behavior (I know it has to do
with model.frame, but not sure how) would also
be greatly appreciated!

Thanks!
--Erik

__
R-help@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.