From: Sean Davis <sdavis2_at_mail.nih.gov>

Date: Tue 03 May 2005 - 00:58:39 EST

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Tue May 03 01:04:25 2005

Date: Tue 03 May 2005 - 00:58:39 EST

- Original Message ----- From: "Christoph Scherber" <Christoph.Scherber@uni-jena.de> To: <r-help@stat.math.ethz.ch> Sent: Monday, May 02, 2005 10:52 AM Subject: [R] "apply" question

> Dear R users,

*>
**> Iīve got a simple question but somehow I canīt find the solution:
**>
**> I have a data frame with columns 1-5 containing one set of integer values,
**> and columns 6-10 containing another set of integer values. Columns 6-10
**> contain NAīs at some places.
**>
**> I now want to calculate
**> (1) the number of values in each row of columns 6-10 that were NAīs
**> (2) the sum of all values on columns 1-5 for which there were no missing
**> values in the corresponding cells of columns 6-10.
**>
**>
**> Example: (letīs call the data frame "data")
**>
**> Col1 Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10
**> 1 2 5 2 3 NA 5 NA 1 4
**> 3 1 4 5 2 6 NA 4 NA 1
**>
**> The result would then be (for the first row)
**> (1) "There were 2 NAīs in columns 6-10."
**> (2) The mean of Columns 1-5 was 2+2+3=7" (because there were NAīs in the
**> 1st and 3rd position in rows 6-10)
**>
**> So far, I know how to calculate the rowSums for the data.frame, but I
**> donīt know how to condition these on the values of columns 6-10
**>
**> rowSums(data[,1:5]) #thatīs straightforward
**> apply(data[,6:19],1,function(x)sum(is.na(x))) #this also works fine
**>
**> But I donīt know how to select just the desired values of columns 1-5 (as
**> described above)
*

tmp <- rowSums(data[apply(data[,6:19],1,function(x) sum(is.na(x)))==0,1:5])

Now, tmp contains only the rowsums for the rows with no NAs in the other columns.

Sean

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Tue May 03 01:04:25 2005

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