[R] is there a way to recursilvely lapply

[Whit Armstrong]

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
>>
>> ______________________________________________
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>> PLEASE do read the posting guide
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>> and provide commented, minimal, self-contained, reproducible code.
>>
>
> --
> 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)
> 1 South Parks Road,                     +44 1865 272866 (PA)
> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
>