R help - Oct 2009 - Creating a list of empty lists

Well here is one more brain-teaser related to assigning stuff into a 
list of list. What if I need to create a new list of empty lists? I have 
actually got a solution to this problem:

     l = list(list())
     for ( i in sequence(length-1) )
     {
         l = list(unlist(l,recursive=FALSE), list())
     }

But it is not very neat to do this in a loop. Are there any cuter ways 
to do this?

Best,
Magnus

On 10/13/2009 03:48 PM, Magnus Torfason wrote:
> l = list(list())
>      for ( i in sequence(length-1) )
>      {
>          l = list(unlist(l,recursive=FALSE), list())
>      }
About this :

 > rep( list(list()), 3 )
[[1]]
list()

[[2]]
list()

[[3]]
list()

Romain

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Live and learn ...

Thank you!

On 10/13/2009 9:57 AM, Romain Francois wrote:
> On 10/13/2009 03:48 PM, Magnus Torfason wrote:
>> l = list(list())
>>      for ( i in sequence(length-1) )
>>      {
>>          l = list(unlist(l,recursive=FALSE), list())
>>      }
> 
> About this :
> 
>  > rep( list(list()), 3 )
> [[1]]
> list()
> 
> [[2]]
> list()
> 
> [[3]]
> list()
> 
> Romain
>

Try this:

replicate(3, list())

On Tue, Oct 13, 2009 at 10:48 AM, Magnus Torfason
<zulutime.net at gmail.com> wrote:
> Well here is one more brain-teaser related to assigning stuff into a list
of
> list. What if I need to create a new list of empty lists? I have actually
> got a solution to this problem:
>
> ? ?l = list(list())
> ? ?for ( i in sequence(length-1) )
> ? ?{
> ? ? ? ?l = list(unlist(l,recursive=FALSE), list())
> ? ?}
>
> But it is not very neat to do this in a loop. Are there any cuter ways to
do
> this?
>
> Best,
> Magnus
>
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> PLEASE do read the posting guide
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>


-- 
Henrique Dallazuanna
Curitiba-Paran?-Brasil
25? 25' 40" S 49? 16' 22" O

On 10/13/2009 10:06 AM, Henrique Dallazuanna wrote:
> Try this:
> 
> replicate(3, list())
Thanks!

I now have three ways to achieve my goal:

1: rep(list(list()), 3)

2: replicate(3, list())

3: Due to the way R recycles arguments, I found that it is enough to 
have construct a list(list()), and then perform an assignment using an 
argument of the length I want (using mapply()). The empty list is then 
recycled enough times to hold the corresponding values.

Best,
Magnus