Thank you very much Rui (and Eloi for your input)... this is (the very
simplified version of) what I will end up using:
J <- 10
N <- 10
y <- matrix(0,N,J)
cols <- rep(c(TRUE, TRUE, FALSE, FALSE), 3)[seq_len(J)]
for(j in which(cols)){
for (q in 1:N){
if(j %% 2){
y[q,j]=1
}else{y[q,j]=2}
}
}
for(j in which(!cols)){
for (q in 1:N){
if(j %% 2){
y[q,j]="A"
}else{y[q,j]="B"}
}
}
Cheers,
Claudia
On Mon, Jul 30, 2012 at 5:38 PM, Mercier Eloi <emerc...@chibi.ubc.ca> wrote:
> Or, assuming you only have 4 different elements :
>
> mat<- matrix(rep(c(1,2,"A", "B"),each=10),10,10, byrow=F)
> mat2 <- as.data.frame(mat)
>
> mat
>
> [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
> [1,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
> [2,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
> [3,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
> [4,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
> [5,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
> [6,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
> [7,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
> [8,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
> [9,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
> [10,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
>
> mat2
> V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
>
> 1 1 2 A B 1 2 A B 1 2
> 2 1 2 A B 1 2 A B 1 2
> 3 1 2 A B 1 2 A B 1 2
> 4 1 2 A B 1 2 A B 1 2
> 5 1 2 A B 1 2 A B 1 2
> 6 1 2 A B 1 2 A B 1 2
> 7 1 2 A B 1 2 A B 1 2
> 8 1 2 A B 1 2 A B 1 2
> 9 1 2 A B 1 2 A B 1 2
> 10 1 2 A B 1 2 A B 1 2
>
> Cheers,
>
> Eloi
>
>
> On 12-07-30 04:28 PM, Rui Barradas wrote:
>
>> Hello,
>>
>> Maybe something along the lines of
>>
>> J <- 10
>> cols <- rep(c(TRUE, TRUE, FALSE, FALSE), 3)[seq_len(J)]
>> for(i in which(cols)) { do something }
>> for(i in which(!cols)) { do something else }
>>
>> Hope this helps,
>>
>> Rui Barradas
>>
>> Em 31-07-2012 00:18, Claudia Penaloza escreveu:
>>
>>> Dear All,
>>> I would like to apply two different "for loops" to each set of four
>>> columns
>>> of a matrix (the loops here are simplifications of the actual loops I
>>> will
>>> be running which involve multiple if/else statements).
>>> I don't know how to "alternate" between the loops depending on which
>>> column
>>> is "running through the loop" at the time.
>>> ## Set up matrix
>>> J <- 10
>>> N <- 10
>>> y <- matrix(0,N,J)
>>> ## Apply this loop to the first two of every four columns ([,1:2],
>>> [,5:6],[,9:10], etc.)
>>> for (q in 1:N){
>>> for(j in 1:J){
>>> if(j %% 2){
>>> y[q,j]=1
>>> }else{y[q,j]=2}
>>> }
>>> }
>>> ## Apply this loop to the next two of every four columns
>>> ([,3:4],[,7:8],[,11:12], etc.)
>>> for (q in 1:N){
>>> for(j in 1:J){
>>> if(j %% 2){
>>> y[q,j]="A"
>>> }else{y[q,j]="B"}
>>> }
>>> }
>>> I want to get something like this (preferably without the quotes):
>>>
>>> y
>>>>
>>> [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
>>> [1,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
>>> [2,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
>>> [3,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
>>> [4,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
>>> [5,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
>>> [6,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
>>> [7,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
>>> [8,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
>>> [9,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
>>> [10,] "1" "2" "A" "B" "1" "2" "A" "B" "1" "2"
>>>
>>>
>>>
>>> Any help greatly appreciated!
>>>
>>> Claudia
>>>
>>> [[alternative HTML version deleted]]
>>>
>>> ______________________________**________________
>>> R-help@r-project.org mailing list
>>> https://stat.ethz.ch/mailman/**listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help>
>>> PLEASE do read the posting guide http://www.R-project.org/**
>>> posting-guide.html <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<https://stat.ethz.ch/mailman/listinfo/r-help>
>> PLEASE do read the posting guide http://www.R-project.org/**
>> posting-guide.html <http://www.R-project.org/posting-guide.html>
>> and provide commented, minimal, self-contained, reproducible code.
>>
>>
>>
>
> --
> Eloi Mercier
> Bioinformatics PhD Student, UBC
> Paul Pavlidis Lab
> 2185 East Mall
> University of British Columbia
> Vancouver BC V6T1Z4
>
>
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