[R] missing values

[Michael Bedward]

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.calandra at 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.lamprianou at manchester.ac.uk
>>
>>
>>
>>
>>
>> ______________________________________________
>> R-help at 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.calandra at uni-hamburg.de
>
> **********
> http://www.for771.uni-bonn.de
> http://webapp5.rrz.uni-hamburg.de/mammals/eng/1525_8_1.php
>
> ______________________________________________
> R-help at r-project.org mailing list
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>