I have solved the issue by checking that the number of layers is bigger than
one. It looks to me like stack() has some problems when being fed only one
layer.

x = character vector

    list.of.files <- lapply(X = list.of.files, FUN = function(x) {
                if (length(x) > 1) {
                    c1 <- raster::stack(x)
                    c1 <- sum(c1, na.rm = TRUE)
                    c1[c1 == 0] <- NA
                }
                if (length(x) == 1) {
                    c1 <- raster(x)
                }
                return(c1)
            })

Cheers,
Roman



On Tue, Nov 9, 2010 at 3:42 PM, Roman Luštrik <roman.lustrik@gmail.com>wrote:

> Dear Listers,
>
> I have a list (list.of.files) of file names (character vector) with n
> number of elements.
>
> List of 9
>  $ 1: chr [1:5] "binned_walker1_1.grd" ...
>  $ 2: chr [1:2] "binned_walker2_1.grd" ...
>  $ 3: chr [1:3] "binned_walker3_1.grd" ...
>  $ 4: chr [1:6] "binned_walker4_1.grd" ...
>  $ 5: chr "binned_walker5_1.grd" ...
>  $ 6: chr [1:4] "binned_walker6_1.grd" ...
>  $ 7: chr [1:6] "binned_walker7_1.grd" ...
>  $ 8: chr [1:4] "binned_walker8_1.grd" ...
>  $ 9: chr [1:3] "binned_walker9_1.grd" ...
>
> If I call stack() on list elements using, for example
>
> stack(list.of.files[[1]])
>
> I get a RasterStack object with appropriate number of layers.
>
> If I call lapply on list.of.files with
>
> lapply(list.of.files, FUN = function(x) stack(x))
>
> I get an error
>
> $`1`
> Error in print(<S4 object of class "RasterStack">) :
>   no slot of name "file" for this object of class "RasterStack"
>
> Can anyone elucidate why the method works "by hand" and not using lapply?
>
> Cheers,
> Roman
>
>
>
> --
> In God we trust, all others bring data.
>



-- 
In God we trust, all others bring data.

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