[R] lapply not reading arguments from the correct environment

[Dimitris Rizopoulos]

subset() was not defined inside myfun(); try this version instead:

myfun <- function () {
    foo <- data.frame(1:10, 10:1)
    foos <- list(foo)
    fooCollumn <- 2
    my.subset <- function(...) subset(...)
    cFoo <-  lapply(foos, my.subset, select = fooCollumn)
    cFoo
}
myfun()


I hope it helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
     http://www.student.kuleuven.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "jiho" <jo.irisson at gmail.com>
To: <r-help at stat.math.ethz.ch>
Sent: Friday, May 18, 2007 4:41 PM
Subject: [R] lapply not reading arguments from the correct environment


> Hello,
>
> I am facing a problem with lapply which I ''''think''' may be a bug.
> This is the most basic function in which I can reproduce it:
>
> myfun <- function()
> {
> foo = data.frame(1:10,10:1)
> foos = list(foo)
> fooCollumn=2
> cFoo = lapply(foos,subset,select=fooCollumn)
> return(cFoo)
> }
>
> I am building a list of dataframes, in each of which I want to keep
> only column 2 (obviously I would not do it this way in real life but
> that's just to demonstrate the bug).
> If I execute the commands inline it works but if I clean my
> environment, then define the function and then execute:
> > myfun()
> I get this error:
> Error in eval(expr, envir, enclos) : object "fooCollumn" not found
> while fooCollumn is defined, in the function, right before lapply. 
> In
> addition, if I define it outside the function and then execute the
> function:
> > fooCollumn=1
> > myfun()
> it works but uses the value defined in the general environment and
> not the one defined in the function.
> This is with R 2.5.0 on both OS X and Linux (Fedora Core 6)
> What did I do wrong? Is this indeed a bug? An intended behavior?
> Thanks in advance.
>
> JiHO
> ---
> http://jo.irisson.free.fr/
>
> ______________________________________________
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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.
> 


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