R help - Jan 2006 - assign object to list

Dear all

I want to generate a list like this:

a <- data.frame(1:10)
attr(a,'myattribute') <- 'something'
b <- data.frame(11:20)
attr(b,'myattribute') <- 'anything'
mylist <- list(a,b)

Is there a way to place the dataframes into the list giving them the 
attribute at the same time?
I don't want to create all the dataframes in my workspace first. I tried 
it with parentheses {}, but it obviously did not work.

Thanks in advance.
Christian

-- 
Christian Bieli, project assistant
Institute of Social and Preventive Medicine
University of Basel, Switzerland
Steinengraben 49
CH-4051 Basel
Tel.: +41 61 270 22 12
Fax:  +41 61 270 22 25
christian.bieli at unibas.ch
www.unibas.ch/ispmbs

On Fri, 20 Jan 2006, Christian Bieli wrote:
> Dear all
>
> I want to generate a list like this:
>
> a <- data.frame(1:10)
> attr(a,'myattribute') <- 'something'
> b <- data.frame(11:20)
> attr(b,'myattribute') <- 'anything'
> mylist <- list(a,b)
>
> Is there a way to place the dataframes into the list giving them the
> attribute at the same time?
Yes, the above worked.
> lapply(mylist, attributes)
> lapply(mylist, function(x) attr(x, "myattribute"))
show you they are there.

What may have confused you is that the print method for data frames does 
not show arbitrary attributes.
> I don't want to create all the dataframes in my workspace first. I
tried
> it with parentheses {}, but it obviously did not work.
>
> Thanks in advance.
> Christian
-- 
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

if you have a list of data frames without the attribute and a 
vector/list of the values for this attributes:

mapply(function(x,y) {attr(x,"names") <- y ; x},
    list(data.frame(1:10), data.frame(11:20)), c("something", 
"anything"), SIMPLIFY=F)


Christian Bieli a ??crit :
>Dear all
>
>I want to generate a list like this:
>
>a <- data.frame(1:10)
>attr(a,'myattribute') <- 'something'
>b <- data.frame(11:20)
>attr(b,'myattribute') <- 'anything'
>mylist <- list(a,b)
>
>Is there a way to place the dataframes into the list giving them the 
>attribute at the same time?
>I don't want to create all the dataframes in my workspace first. I tried
>it with parentheses {}, but it obviously did not work.
>
>Thanks in advance.
>Christian
>
>  
>