R help - Jan 2009 - function return output

Hi, I wrote the function which outputs a matrix 'c' and a single value
'd',
as follows (simplified example):
procedure <- function(a,b){
...
list(c,d)
}
now I want to use 'c' and 'd' in code as follows:
d <- matrix(0,1,1)
value <- procedure(a,b)
and d[1,1] <- value[2] breaks telling that:
Error in d[1, 1] : incorrect number of dimensions
What I did wrong??, best, robert



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threshold wrote:
> Hi, I wrote the function which outputs a matrix 'c' and a single
value 'd',
> as follows (simplified example):
> procedure <- function(a,b){
> ...
> list(c,d)
> }
> now I want to use 'c' and 'd' in code as follows:
> d <- matrix(0,1,1)
> value <- procedure(a,b)
> and d[1,1] <- value[2] breaks telling that:
> Error in d[1, 1] : incorrect number of dimensions
> What I did wrong??, best, robert
Probably "value" is a list, hence value[2] is also a list and you
cannot
assign a list to an element of a *numeric* matrix. I guess you want 
value[[2]].
Anyway, it is all a guess since we do not know what your "procedure()"
returns ....


Uwe Ligges



> 
> 
>

On Jan 16, 2009, at 5:22 AM, threshold wrote:
>
> Hi, I wrote the function which outputs a matrix 'c' and a single  
> value 'd',
> as follows (simplified example):
> procedure <- function(a,b){
> ...
> list(c,d)
> }
> now I want to use 'c' and 'd' in code as follows:
> d <- matrix(0,1,1)
> value <- procedure(a,b)
> and d[1,1] <- value[2] breaks telling that:
> Error in d[1, 1] : incorrect number of dimensions
> What I did wrong??, best, robert
Who knows? No reproducible code.

The usual way of accessing just the second element of a list would be  
value[[2]]. value[2] will be a list that contains whatever was "d",  
rather than what was "d" in the procedure() call itself. It will not  
have the name "d". It is possible to use the same names inside and  
outside a function but it may be more clear for beginners to keep them  
separate.

-- 
David Winsemius