is there a way to recursilvely lapply

Thanks, Gabor and Prof. Ripley.

Sorry for the oversight.

I grepped the lapply help for recursive prior to sending my question.

why does it appear as "*r*ecursive" in the help file? or is that just
a formating problem on my machine?

-Whit


On Thu, Dec 11, 2008 at 3:13 PM, Prof Brian Ripley
<ripley at stats.ox.ac.uk> wrote:

On Thu, 11 Dec 2008, Whit Armstrong wrote:

for a simple example:

x <- list()
x[["a"]] <- list(a=c(1,2,3),b=c(3,4,5))
x[["b"]] <- list(a=c(6,7,8),b=c(9,10,11))

lapply(x,sum)


this fails w/
Error in FUN(X[[1L]], ...) : invalid 'type' (list) of argument

Just wondering if I have overlooked something obvious.

rapply?  Which is linked from ?lapply (I just checked).  Perhaps

rapply(x, sum)

a.a a.b b.a b.b
 6  12  21  30

or

rapply(x, sum, how="list")

$a
$a$a
[1] 6
.....

one can also do:

lapply(x,lapply,sum)

but that assumes that you already know how many levels you have, and
that all the levels are consistent.

-Whit

--
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
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