[R] using lapply()

[dxc13]

Thank you, this works perfectly!




Dimitris Rizopoulos wrote:
> 
> try the following:
> 
> delta <- c(2.5, 2.5, 1)
> v <- list(
>     matrix(round(rnorm(70, 2), 2), 5, 14),
>     matrix(round(rnorm(70, 2), 2), 5, 14),
>     matrix(round(rnorm(70, 2), 1), 5, 14)
> )
> 
> v
> mapply(function(x, y){ x[x > y] <- NA; x }, v, delta, SIMPLIFY = 
> FALSE)
> 
> 
> I hope it helps.
> 
> 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
> 
> 
> ----- Original Message ----- 
> From: "dxc13" <dxc13 at health.state.ny.us>
> To: <r-help at r-project.org>
> Sent: Tuesday, January 08, 2008 6:11 PM
> Subject: [R] using lapply()
> 
> 
>>
>> useR's,
>>
>> I am trying to find a quick way to change some values in a list that 
>> are
>> subject to a condition to be NA.  Consider the 3x1 matrix:
>>
>> delta <- matrix(c(2.5,2.5,1), nrow = 1)
>>
>> And consider the list named v that has 3 elements
>>> v
>> v[[1]]
>>       [,1] [,2]  [,3]  [,4]  [,5]  [,6]  [,7]  [,8] [,9] [,10] 
>> [,11] [,12]
>> [,13] [,14]
>> [1,] 4.25 3.25 2.25 1.25 0.25 0.75 1.75 2.75 3.75  4.25  3.25  2.25 
>> 1.25
>> 0.25
>> [2,] 1.25 0.25 0.75 1.75 2.75 3.75 4.75 5.75 6.75  1.25  0.25  0.75 
>> 1.75
>> 2.75
>> [3,] 7.25 6.25 5.25 4.25 3.25 2.25 1.25 0.25 0.75  7.25  6.25  5.25 
>> 4.25
>> 3.25
>> [4,] 3.25 2.25 1.25 0.25 0.75 1.75 2.75 3.75 4.75  3.25  2.25  1.25 
>> 0.25
>> 0.75
>> [5,] 6.25 5.25 4.25 3.25 2.25 1.25 0.25 0.75 1.75  6.25  5.25  4.25 
>> 3.25
>> 2.25
>>
>> v[[2]]
>>       [,1]  [,2]  [,3] [,4]  [,5]  [,6]  [,7]  [,8] [,9] [,10] [,11] 
>> [,12]
>> [,13] [,14]
>> [1,] 9.25 9.25 9.25 9.25 9.25 9.25 9.25 9.25 9.25  8.25  8.25  8.25 
>> 8.25
>> 8.25
>> [2,] 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25  6.25  6.25  6.25 
>> 6.25
>> 6.25
>> [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,] 4.25 4.25 4.25 4.25 4.25 4.25 4.25 4.25 4.25  3.25  3.25  3.25 
>> 3.25
>> 3.25
>> [5,] 6.25 6.25 6.25 6.25 6.25 6.25 6.25 6.25 6.25  5.25  5.25  5.25 
>> 5.25
>> 5.25
>>
>> v[[3]]
>>      [,1] [,2]  [,3] [,4] [,5] [,6] [,7] [,8]  [,9] [,10] [,11] 
>> [,12] [,13]
>> [,14]
>> [1,]  0.5  0.5  0.5  0.5  0.5  0.5  0.5  0.5  0.5   0.5   0.5   0.5 
>> 0.5
>> 0.5
>> [2,]  1.5  1.5  1.5  1.5  1.5  1.5  1.5  1.5  1.5   1.5   1.5   1.5 
>> 1.5
>> 1.5
>> [3,]  2.5  2.5  2.5  2.5  2.5  2.5  2.5  2.5  2.5   2.5   2.5   2.5 
>> 2.5
>> 2.5
>> [4,]  3.5  3.5  3.5  3.5  3.5  3.5  3.5  3.5  3.5   3.5   3.5   3.5 
>> 3.5
>> 3.5
>> [5,]  4.5  4.5  4.5  4.5  4.5  4.5  4.5  4.5  4.5   4.5   4.5   4.5 
>> 4.5
>> 4.5
>>
>> The first element of the matrix delta (2.5) corresponds to the first 
>> list
>> element v[[1]], and so on...
>>
>> What I want to do is to set any values in this list that are greater 
>> than
>> its corresponding delta to be NA.  For example, if any value in 
>> v[[1]] is
>> greater than 2.5 than set it to NA, and similarly for v[[2]].  If 
>> any value
>> in v[[3]] is > 1, then set it NA.
>>
>> Can this be done using lapply or some other quick, efficient way? 
>> Hope this
>> makes sense.
>> Thanks,
>>
>> Derek
>> -- 
>> View this message in context: 
>> http://www.nabble.com/using-lapply%28%29-tp14693921p14693921.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
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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.
>> 
> 
> 
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> 
> ______________________________________________
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