[R] piece wise application of functions

[Tom Blackwell]

Itay  -

If it were my problem, I would re-structure the task around the
existing capabilities of  lapply().  In particular, I would
concatenate the three lists of functions, then write a wrapper
function which takes three arguments:  an index, a list of
functions and a data set.  Then I would call  lapply()  twice
to get the result you appear to be asking for.  Here's a rough
example, untested, which may not work exactly for your situation.

miss.all <- c(missgp0, missgp1, missgp2)
wrapper  <- function(i, ff, d)  {ff[[i]](d)}
result.1 <- unlist(lapply(seq(9), wrapper, miss.all, snps.missgp[["ic"]]))
result.2 <- unlist(lapply(seq(9), wrapper, miss.all, strs.missgp[["ic"]]))
gaps     <- c(  #  nine multiples of 1e+6 which describe the nine functions )
result   <- cbind(gaps=gaps, snps=result.1, strs=result.2)

In this case,  result  is a matrix, not a data frame, but you can
easily convert between the two.

HTH  -  tom blackwell  -  u michigan medical school  -  ann arbor  -

On Thu, 19 Feb 2004, Itay Furman wrote:

>
> Dear all,
>
> After struggling for some time with *apply() and eva() without
> success, I decided to ask for help.
>
> I have 3 lists labeled with, each contains 3 different
> interpolation functions with identical names:
>
> > names(missgp0)
> [1] "spl.1mb" "spl.2mb" "spl.5mb"
> >
> > names(missgp1)
> [1] "spl.1mb" "spl.2mb" "spl.5mb"
> >
> > names(missgp2)
> [1] "spl.1mb" "spl.2mb" "spl.5mb"
> >
>
> (
> In case it matters the functions accept and return one argument:
> block.size <- spl.1mb(ic)
> )
>
> Then, I have 2 data frames with identical structure:
>
> > snps.missgp
>   intvl.mb    ic
> 1    1e+06 0.597
> 2    2e+06 0.504
> 3    5e+06 0.327
> 4    1e+07 0.204
> >
>
> > strs.missgp
>   intvl.mb      ic
> 1    1e+06 0.67200
> 2    2e+06 0.62325
> 3    5e+06 0.51000
> 4    1e+07 0.38775
> >
>
> I would like to apply the functions on these data frames
> piece-wise and create a data frame per function _list_.
>
> So I am looking for a final output like this:
>
> > case0
>     gap	 snps	strs
> 1 1e+06  ..	..
> 2 2e+06  ..	..
> 3 5e+06  ..	..
>
> Here, case0$snps[1] is, for example, the result of applying the
> function in  missgp0[1] on the entry snps.missgp$ic[1];
> and, case0$strs[1] is the result of applying the same function
> on strs.missgp$ic[1].
>
> Then, I want to repeat the whole thing with missgp1,2  instead
> of missgp0, generating case1,2 data frames.
>
> How should I do it?
>
>
> 	Thanks in advance,
> 	Itay Furman
>
> --------------------------------------------------------------------
> itayf at fhcrc.org			Fred Hutchinson Cancer Research Center
>
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