R help - Dec 2024 - outer() is not working with my simple function

Hi,

I have below code

FN1 = function(x, y) 3

outer(1:9, 1:9, FN1)

With above I get error as below

Error in dim(robj) <- c(dX, dY) :

  dims [product 81] do not match the length of object [1]

Could you please help to understand why is it failing? I am just
expecting to get a matrix with all elements as 3

outer() expects a return value with the same length as that of x.

You could change the code to rep(3, length(x))

Or if you don't want to change the code of the function, you could make a
wrapper and use that instead:
function (x, y)
{
    v <- FN1(x, y)
    if (length(v) != 1) v else rep(v, length(x))
}


On Tue, Dec 10, 2024, 11:37 Christofer Bogaso <bogaso.christofer at
gmail.com>
wrote:
> Hi,
>
> I have below code
>
> FN1 = function(x, y) 3
>
> outer(1:9, 1:9, FN1)
>
> With above I get error as below
>
> Error in dim(robj) <- c(dX, dY) :
>
>   dims [product 81] do not match the length of object [1]
>
> Could you please help to understand why is it failing? I am just
> expecting to get a matrix with all elements as 3
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
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> and provide commented, minimal, self-contained, reproducible code.
>
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On 2024-12-10 11:36 a.m., Christofer Bogaso wrote:
> Hi,
> 
> I have below code
> 
> FN1 = function(x, y) 3
> 
> outer(1:9, 1:9, FN1)
> 
> With above I get error as below
> 
> Error in dim(robj) <- c(dX, dY) :
> 
>    dims [product 81] do not match the length of object [1]
> 
> Could you please help to understand why is it failing? I am just
> expecting to get a matrix with all elements as 3
The help page says this about the function:  "It must be a vectorized 
function (or the name of one) expecting at least two arguments and 
returning a value with the same length as the first (and the second)." 
So your function could be

   FN1 <- function(x, y) rep_len(3, length(x))

and it would work.

Duncan Murdoch