[R] Lists and functions in data.frame?

[Rainer M Krug]

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On 12/08/2010 11:22 AM, jim holtman wrote:
> It sounds like you want to use a "list" instead of a dataframe,

No - I would like to have a data,frame. I am aware of the differences,
but as far as I understand, each column in a data.frame can have a
differnt type. So I thought that the type of column fun could be
"function", column no "list", column value "numeric" and column b
"boolean".

> especially if the elements are a different length.

OK - forget about the different length - I could convert the vectors to
lists, and store them as lists in the data.frame (if possible).


> 
>> d <- list()  # initialize
>> d[[length(d) + 1]] <- list()  # extend
>> d[[length(d)]]$fun <- sin  # add a function
>> d[[length(d) + 1]] <- list()  # extend again
>> d[[length(d)]]$fun <- cos  # another function
>> d[[length(d)]]$val <- 42  # some value
>> d
> [[1]]
> [[1]]$fun
> function (x)  .Primitive("sin")
> 
> 
> [[2]]
> [[2]]$fun
> function (x)  .Primitive("cos")
> 
> [[2]]$val
> [1] 42

Sure - that would work, but I would prefer to have it in a data.frame.

Cheers,

Rainer
> 
> 
> On Wed, Dec 8, 2010 at 5:08 AM, Rainer M Krug <r.m.krug at gmail.com> wrote:
> Hi
> 
> I would like to have a data.frame, where one column contains functions,
> and another one lists. i.e.:
> 
> FUN <- function(l) {return(l$a+l$b+l$c}
> LIST <- list(a=1, b=2, c=3)
> 
> d <- data.frame(fun=FUN, no=LIST, value=2, b=TRUE)
> 
> FUN <- function(l) {return(l$a*l$b*l$c}
> LIST <- list(a=4, b=5, c=6)
> 
> d <- rbind(d, data.frame(fun=FUN, no=LIST, value=2, b=FALSE)
> 
> I would like
> d$FUN[1](d$l[1] == 6
> to be TRUE
> 
> I want to use it to save a parameterset for a simulation model, which
> consists of functions, lists, and vectors of different length.
> 
> Is this possible?
> 
> 
> Cheers,
> 
> Rainer
> 
>>
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- -- 
Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation
Biology, UCT), Dipl. Phys. (Germany)

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