[R] counting missing values

[Uwe Ligges]

vincent.stoliaroff at socgen.com wrote:

> Hello R lovers
> I have written a little cute function to count the number of missing value
> per row in a matrix and return the percentage of missing value
> 
> it takes a lot of time to run with a 1000 rows matrix
> 
> I'd like to know if there is a function already implemented to count the
> number of occurence of a given values in a vector
> 
> 
> For information,
> here is the function
> count<-0
> for (i in 1:nrow(Matrix))
>       {
>       for (j in 1:ncol(Matrix)) {if (is.na(Matrix[i,j])) count<-count+1}
>       Result[i,1]<-((count/(ncol(Matrix)))*100);
>       count<-0
>       }
> Result
> 
> thanks for any help
> Vincent

Well, it's pretty easy to do it:

apply(Matrix, 1, function(x) sum(is.na(x))) / ncol(Matrix) * 100

Uwe Ligges