On 12-07-31 02:38 PM, Claudia Penaloza wrote:
> Thank you very much Rui (and Eloi for your input)... this is (the very 
> simplified version of) what I will end up using:
Could we get the extended version ? Because right now, I don't know why 
you need such complicated code that can be done in 1 line.
> 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"}
>     }
>   }
>
There is no need for a double loop (on N) :

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)){
    if(j %% 2){
       y[,j]=1
       }else{y[,j]=2}
   }
for(j in which(!cols)){
     if(j %% 2){
       y[,j]="A"
       }else{y[,j]="B"}
   }

if you really wants to use this code.

Cheers,

Eloi
> Cheers,
> Claudia
> On Mon, Jul 30, 2012 at 5:38 PM, Mercier Eloi <emercier@chibi.ubc.ca 
> <mailto:emercier@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 <tel:31-07-2012%2000>: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 <mailto:R-help@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.
>
>
>         ______________________________________________
>         R-help@r-project.org <mailto:R-help@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.
>
>
>
>
>     -- 
>     Eloi Mercier
>     Bioinformatics PhD Student, UBC
>     Paul Pavlidis Lab
>     2185 East Mall
>     University of British Columbia
>     Vancouver BC V6T1Z4
>
>


-- 
Eloi Mercier
Bioinformatics PhD Student, UBC
Paul Pavlidis Lab
2185 East Mall
University of British Columbia
Vancouver BC V6T1Z4


	[[alternative HTML version deleted]]

