Help using mapply to run multiple models

Just so I can see if I understand ... that is because `as.name` will evaluate `modelType`
whereas as.name("modelType") would look for the function `modelType` and not find
such a name in the namespace? 
Almost.  as.name(modelType) will evaluate modelType so modelType could be a
character string or a name.   as.name itself does not do any lookups - that is eval's job.
When eval() is given a name object it looks it up.

So modelType needs to be a language-object and `f`
needs to be called with:

f(glm, ....) rather than f("glm", ...)
If you use as.name(modelType) then you could call f("glm",...).

f(glm, ...) does not pass a name into the function f, it passes in the object
named "glm" (usually the function in package:stats by that name).
as.name(glm) returns garbage.  If you wanted to be able to call
  f(glm, predictors, response)
you could just use
  call[[1]] <- modelType
in f().  I didn't recommend that because then the call attributes of glm's output
does not look nice.  You can write code so that both f("glm",...) and f(glm,...) work
but I usually prefer not to load up functions with so much heuristic argument
processing (e.g., how should it deal with 'func<-"glm" ; f(func,...)' and the like).
So by the time the function `f` "saw" its arguments from a call:  `f(glm, ...) `, the name of the function would already have been removed and you would just be getting the argument list attached to the function body and as.name() would make a hash of it .... as we saw in the original portion of this question.
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com

-----Original Message-----
From: David Winsemius [mailto:dwinsemius at comcast.net]
Sent: Thursday, December 19, 2013 11:31 AM
To: William Dunlap
Cc: Simon Kiss; r-help at r-project.org
Subject: Re: [R] Help using mapply to run multiple models

On Dec 19, 2013, at 11:10 AM, William Dunlap wrote:

             call[[1]] <- quote(modelType) # '
makes call[[1]] the same as as.name("modelType").  You want
as.name(modelType).
Just so I can see if I understand ... that is because `as.name` will evaluate `modelType`
whereas as.name("modelType") would look for the function `modelType` and not find
such a name in the namespace? So modelType needs to be a language-object and `f`
needs to be called with:

f(glm, ....) rather than f("glm", ...)

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com

-----Original Message-----
From: Simon Kiss [mailto:sjkiss at gmail.com]
Sent: Thursday, December 19, 2013 10:56 AM
To: William Dunlap
Cc: Dennis Murphy; r-help at r-project.org
Subject: Re: [R] Help using mapply to run multiple models

Hello Bill, that is fantastic and it's quite a bit above what I could write. Is there a way
to
make the model type an argument to the function so that you can specify whether
one is
running glm, lm and such?
I tried to modify it by inserting an argument modelType below, but that doesn't work.
Yours, simon Kiss
f <- function (modelType, responseName, predictorNames, data, ..., envir =
parent.frame())
 {
     call <- match.call()
     call$formula <- formula(envir = envir, paste(responseName, sep = " ~ ",
         paste0("`", predictorNames, "`", collapse = " + ")))
             call[[1]] <- quote(modelType) # '
     call$responseName <- NULL # omit responseName=
     call$predictorNames <- NULL # omit 'predictorNames='
             eval(call, envir = envir)
 }
On 2013-12-18, at 3:07 PM, William Dunlap <wdunlap at tibco.com> wrote:

f <- function (responseName, predictorNames, data, ..., envir = parent.frame())
 {
     call <- match.call()
     call$formula <- formula(envir = envir, paste(responseName, sep = " ~ ",
         paste0("`", predictorNames, "`", collapse = " + ")))
             call[[1]] <- quote(glm) # 'f' -> 'glm'
     call$responseName <- NULL # omit responseName=
     call$predictorNames <- NULL # omit 'predictorNames='
             eval(call, envir = envir)
 }
as in
 z <- lapply(list(c("hp","drat"), c("cyl"), c("am","gear")), FUN=function(preds)f("carb",
preds, data=mtcars, family=poisson))
 lapply(z, summary)
*********************************
Simon J. Kiss, PhD
Assistant Professor, Wilfrid Laurier University
73 George Street
Brantford, Ontario, Canada
N3T 2C9
Cell: +1 905 746 7606

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David Winsemius
Alameda, CA, USA

David Winsemius
Alameda, CA, USA

Help using mapply to run multiple models

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