[R] Problem applying "outer" to a list of functions

[Joshua Wiley]

Hi,

On Sat, Oct 16, 2010 at 9:52 AM, jschamel <jtschamel at alaska.edu> wrote:
>
> I'm trying to construct an array with output from the application of
> homogeneous input to a bunch of different functions (my final goal is to
> easily analyze running time of a lot of competing functions and summarize
> the results).  In my current iteration, however, only the first function in
> the list is being applied, and I'm not sure why.

Because you only call the first element of the list, fl[[1]], that is
the foo function.  You might play around with a simple example in
outer not involving functions to get a better feel for what it does.

  Here's my dummy code with
> output
>
>
>> foo <- function(x){paste('foo(',x,')',sep='')}
>> bar <- function(x){paste('bar(',x,')',sep='')}
>> outer(list(foo,bar),1:2,function(fl,x){fl[[1]](x)})
>     [,1]     [,2]
> [1,] "foo(1)" "foo(2)"
> [2,] "foo(1)" "foo(2)"
>
>
> Any insight would be appreciated!  Thanks!

For your overall goal, here is how I would call a bunch of functions
with the same arguments:

lapply(list(foo, bar), do.call, list(1:2))

Cheers

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-- 
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/