And just to add to Ivan's comment, if you are using the rowSums or colSums functions with a matrix or data.frame they also have the na.rm argument.
Michael On 1 December 2010 20:16, Ivan Calandra <ivan.calan...@uni-hamburg.de> wrote: > Hi, > > (a) sum() and mean() have a na.rm argument that should be set to TRUE. > > (b) let's try with an example: > x <- c(1:5, NA, NA, 6:10, NA) > x[is.na(x)] <- 0 ## replace NAs by 0 > > HTH, > Ivan > > > Le 12/1/2010 10:00, Iasonas Lamprianou a écrit : >> >> Dear all, >> i have spent a lot of time trying to solve this problem, but I am sure >> that >> there must be a simple solution. So, as a last resort, I am coming back to >> you >> again. I have a dataset with some (almost random) values in many >> variables. Lets >> say that the dataset represents the scores of students to test questions. >> What I >> need to do is to sum the scores for each student. However, wherever there >> is a >> missing (NA) value, I cannot get the total score. How can I compute the >> total >> score and the average per question (a) by ignoring the missing responses, >> (b) by >> assuming that a missing response is a zero? >> Thank you for the response >> >> >> Dr. Iasonas Lamprianou >> >> >> >> >> Assistant Professor (Educational Research and Evaluation) >> Department of Education Sciences >> European University-Cyprus >> P.O. Box 22006 >> 1516 Nicosia >> Cyprus >> Tel.: +357-22-713178 >> Fax: +357-22-590539 >> >> >> >> >> Honorary Research Fellow >> Department of Education >> The University of Manchester >> Oxford Road, Manchester M13 9PL, UK >> Tel. 0044 161 275 3485 >> iasonas.lampria...@manchester.ac.uk >> >> >> >> >> >> ______________________________________________ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide >> http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. >> > > -- > Ivan CALANDRA > PhD Student > University of Hamburg > Biozentrum Grindel und Zoologisches Museum > Abt. Säugetiere > Martin-Luther-King-Platz 3 > D-20146 Hamburg, GERMANY > +49(0)40 42838 6231 > ivan.calan...@uni-hamburg.de > > ********** > http://www.for771.uni-bonn.de > http://webapp5.rrz.uni-hamburg.de/mammals/eng/1525_8_1.php > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
