counting missing values

From: Uwe Ligges [mailto:ligges at statistik.uni-dortmund.de]

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