[R] Dynamic string as element name in a list

[Paul Lemmens]

Hi,

Sorry yes, I forgot to give comment about the lapply().

>  >  foo <- function(x) {
>  >  out <- list()
>  >  lapply(x$clipno, function(c) {
>  >   clipname <- x$clipname
>  >   # stuff
>  >
>  >   out[[clipname]] <- rnorm(5)
>  >  })
>  >  return(out)
>  >  }
>  >

So x is a dataframe with the data from one subject that has viewed
multiple clips in two variations. x contains both the responses as
well as info about the clips in factors and responses in integers. So
for each clip (using function(c) call in lapply() to be able to
access/subset data from x), I extract the name and other info (using
c), store that info in a list element named after the clip. Finally
return the full list of clips with associated data.

Mvg,
Paul


On Thu, Mar 27, 2008 at 3:23 PM, Henrique Dallazuanna <wwwhsd at gmail.com> wrote:
> HI,
>
>  I don't understand why you're using lapply.
>
>  Please provide a example of your 'x' data.frame
>
>  str(x)
>
>
>  On 27/03/2008, Paul Lemmens <paul.lemmens at gmail.com> wrote:
>
>
> > Hi Henrique,
>  >
>  >
>  >  On Thu, Mar 27, 2008 at 2:52 PM, Henrique Dallazuanna <wwwhsd at gmail.com> wrote:
>  >  > Try this:
>  >  >
>  >  >  foo <- function(x)
>  >  >  {
>  >  >  clipname <- "LK"
>  >  >  out <- list()
>  >  >  out[[clipname]] <- rnorm(5)
>  >  >  return(out)
>  >  > }
>  >
>  > That easy ... Hadn't thought of it.  But now I have a refinement in foo()
>  >
>  >  foo <- function(x) {
>  >  out <- list()
>  >  lapply(x$clipno, function(c) {
>  >   clipname <- x$clipname
>  >   # stuff
>  >
>  >   out[[clipname]] <- rnorm(5)
>  >  })
>  >  return(out)
>  >  }
>  >
>  >
>  > But this returns the/an empty list?
>  >
>  >
>  >  Best regards,
>  >
>  > Paul Lemmens
>  >
>
>
> >  ______________________________________________
>  >  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.
>  >
>
>
>  --
>  Henrique Dallazuanna
>  Curitiba-Paraná-Brasil
>  25° 25' 40" S 49° 16' 22" O
>