is there a way to recursilvely lapply

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

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Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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is there a way to recursilvely lapply

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