Hello,
Maybe the function could return a special value, such as zero.
Since a column with that number doesn't exist, the code executed afterward
would simply move on to the second greatest correlation.
The function would then become
get.max.cor <- function(station, mat){
mat[row(mat) == col(mat)] <- -Inf
if(sum(is.na(mat[station, ])) == ncol(mat) - 1)
0
else
which( mat[station, ] == max(mat[station, ], na.rm=TRUE) )
}
df1 <- read.table(text="
file1 file2 file3
file1 1 NA 0.8
file2 NA 1 NA
file3 0.8 NA 1
", header=TRUE)
get.max.cor("file2", df1)
Hope this helps,
Rui Barradas
jeff6868 wrote
>
> Hi everybody,
>
> I have a small question about R.
> I'm doing some correlation matrices between my files. These files contains
> each 4 columns of data.
> These data files contains missing data too. It could happen sometimes that
> in one file, one of the 4 columns contains only missing data NA. As I'm
> doing correlations between the same columns of each files, I get a
> correlation matrix with a column containing only NAs such like this:
>
> file1 file 2 file 3
> file1 1 NA 0.8
> file2 NA 1 NA
> file3 0.8 NA 1
>
> For file2, I have no correlation coefficient.
> My function is looking for the highest correlation coefficient for each
> file. But I have an error message due to this.
> My question is: how can I say to the function: don't do any calculation if
> you see only NAs for the file you're working on? The aim of this function
> is to automatize this calculation for 300 files.
> I tried by adding: na.rm=TRUE, but it stills wants to do the calculation
> for the file containing only NAs (error: 0 (non-NA) cases).
> Could you tell me what I should add in my function? Thanks a lot!
>
> get.max.cor <- function(station, mat){
> mat[row(mat) == col(mat)] <- -Inf
> which( mat[station, ] == max(mat[station, ], na.rm=TRUE) )
> }
>
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