[R] using mapply()
Dimitris Rizopoulos
Dimitris.Rizopoulos at med.kuleuven.be
Tue Jan 8 21:06:00 CET 2008
do you mean the following?:
out <- rowMeans(matrix(unlist(res), ncol = length(res)))
dim(out) <- dim(res[[1]])
out
Best,
Dimitris
----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven
Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
http://www.student.kuleuven.be/~m0390867/dimitris.htm
Quoting dxc13 <dxc13 at health.state.ny.us>:
>
> useR's,
>
> This is a follow up question to one I previously asked. Consider the
> 3-element list below
>
>> res
> [[1]]
> [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
> [,13] [,14]
> [1,] NA NA NA 1.25 0.25 0.75 NA NA NA NA NA NA 1.25
> 0.25
> [2,] 1.25 0.25 0.75 NA NA NA NA NA NA 1.25 0.25 0.75 NA
> NA
> [3,] NA NA NA NA NA NA 1.25 0.25 0.75 NA NA NA NA
> NA
> [4,] NA NA 1.25 0.25 0.75 NA NA NA NA NA NA 1.25 0.25
> 0.75
> [5,] NA NA NA NA NA 1.25 0.25 0.75 NA NA NA NA NA
> NA
>
> [[2]]
> [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
> [,13] [,14]
> [1,] NA NA NA NA NA NA NA NA NA NA NA NA NA
> 1.25
> [2,] 1.25 NA NA NA NA NA NA NA NA NA NA NA NA
> NA
> [3,] 1.25 1.25 1.25 1.25 1.25 1.25 1.25 1.25 1.25 0.25 0.25 0.25 0.25
> 0.25
> [4,] NA NA NA NA NA NA NA NA NA NA NA NA NA
> NA
> [5,] NA NA NA NA NA 1.25 NA NA NA NA NA NA NA
> NA
>
> [[3]]
> [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
> [,13] [,14]
> [1,] NA NA NA NA NA NA NA NA NA NA NA NA NA
> 1.25
> [2,] 0.25 NA NA NA NA NA NA NA NA NA NA NA NA
> NA
> [3,] 1.25 1.25 1.25 1.25 1.25 1.25 1.25 1.25 1.25 0.25 0.25 0.25 0.25
> 0.25
> [4,] NA NA NA NA NA NA NA NA NA NA NA NA NA
> NA
> [5,] NA NA NA NA NA 0.25 NA NA NA NA NA NA NA
> NA
>
> What I want to do is find the values that are not NA simultaneously for each
> value in each element of the list, and then average these numbers and store
> them in a 14x1 vector. For example, in position (2,1) in each of the 3
> elements of the res list, there is a value, 1.25 in [[1]] and [[2]], 0.25 in
> [[3]]. Since there is a value in this position in all elements of the list
> I want to average these numbers: (1.25+1.25+0.25)/3 and store this value in
> a numeric vector. So, if there are not 3 values to average, this means
> that a given position (i,j) does not have a value in each element of the
> list and thus I want to store NA in the 14x1 vector. In the end, the 14x1
> vector will be mixed with values and NA's or NaN's.
>
> Does anyone know a efficient way to do this? Maybe using mapply()? I hope
> it is clear. Thank you for any input.
>
> Derek
> --
> View this message in context:
> http://www.nabble.com/using-mapply%28%29-tp14697351p14697351.html
> Sent from the R help mailing list archive at Nabble.com.
>
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