R help - Feb 2008 - reshape question

I know there are a lot of reshape questions on the mailing list, but I  
haven't been able to find an answer to this particular issue.

I am trying to get a datafame structured like this:

 > sub <- rep(1:5)
 > ta1 <- rep(1,5)
 > ta2 <- rep(2,5)
 > tb1<- rep(3,5)
 > tb2 <- rep(4,5)
 > DF <- data.frame(sub,ta1,ta2,tb1,tb2)
 > DF
   sub ta1 ta2 tb1 tb2
1   1   1   2   3   4
2   2   1   2   3   4
3   3   1   2   3   4
4   4   1   2   3   4
5   5   1   2   3   4

into a form like this:

     sub time x1 x2
1.1   1    1  1  3
1.2   1    2  2  4
2.1   2    1  1  3
2.2   2    2  2  4
3.1   3    1  1  3
3.2   3    2  2  4
4.1   4    1  1  3
4.2   4    2  2  4
5.1   5    1  1  3
5.2   5    2  2  4

using the "reshape" command. But when I try reshaping I don't get
the
desired structure:

 > DF.L <- reshape(DF, varying = 2:5, idvar="sub", v.names =
c("x1",
"x2"), times=c(1,2), direction="long")
 > library(doBy)
 > orderBy(~sub, data=DF.L)
     sub time x1 x2
1.1   1    1  1  2
1.2   1    2  3  4
2.1   2    1  1  2
2.2   2    2  3  4
3.1   3    1  1  2
3.2   3    2  3  4
4.1   4    1  1  2
4.2   4    2  3  4
5.1   5    1  1  2
5.2   5    2  3  4

I can get the desired result by rearranging the original dataframe, like
 > DF2 <- data.frame(sub,ta1,tb1,ta2,tb2)

before running the reshape command, but I'm hoping someone knows a way  
to do the desired reshaping without this step, as it becomes very time  
consuming with large numbers of repeated measurements.

Thanks,
Ista

On 2/8/2008 9:15 AM, Ista Zahn wrote:
> I know there are a lot of reshape questions on the mailing list, but I  
> haven't been able to find an answer to this particular issue.
> 
> I am trying to get a datafame structured like this:
> 
>  > sub <- rep(1:5)
>  > ta1 <- rep(1,5)
>  > ta2 <- rep(2,5)
>  > tb1<- rep(3,5)
>  > tb2 <- rep(4,5)
>  > DF <- data.frame(sub,ta1,ta2,tb1,tb2)
>  > DF
>    sub ta1 ta2 tb1 tb2
> 1   1   1   2   3   4
> 2   2   1   2   3   4
> 3   3   1   2   3   4
> 4   4   1   2   3   4
> 5   5   1   2   3   4
> 
> into a form like this:
> 
>      sub time x1 x2
> 1.1   1    1  1  3
> 1.2   1    2  2  4
> 2.1   2    1  1  3
> 2.2   2    2  2  4
> 3.1   3    1  1  3
> 3.2   3    2  2  4
> 4.1   4    1  1  3
> 4.2   4    2  2  4
> 5.1   5    1  1  3
> 5.2   5    2  2  4
> 
> using the "reshape" command. But when I try reshaping I don't
get the
> desired structure:
> 
>  > DF.L <- reshape(DF, varying = 2:5, idvar="sub", v.names
= c("x1",
> "x2"), times=c(1,2), direction="long")
>  > library(doBy)
>  > orderBy(~sub, data=DF.L)
>      sub time x1 x2
> 1.1   1    1  1  2
> 1.2   1    2  3  4
> 2.1   2    1  1  2
> 2.2   2    2  3  4
> 3.1   3    1  1  2
> 3.2   3    2  3  4
> 4.1   4    1  1  2
> 4.2   4    2  3  4
> 5.1   5    1  1  2
> 5.2   5    2  3  4
   The varying argument to reshape() can be a list.  For example:

DF.long <- reshape(DF, varying = list(c("ta1","ta2"),
                                       c("tb1","tb2")),
                        idvar="sub",
                        v.names = c("x1","x2"),
                        times=c(1,2),
                        direction="long")

DF.long[order(DF.long$sub),]

     sub time x1 x2
1.1   1    1  1  3
1.2   1    2  2  4
2.1   2    1  1  3
2.2   2    2  2  4
3.1   3    1  1  3
3.2   3    2  2  4
4.1   4    1  1  3
4.2   4    2  2  4
5.1   5    1  1  3
5.2   5    2  2  4
> I can get the desired result by rearranging the original dataframe, like
>  > DF2 <- data.frame(sub,ta1,tb1,ta2,tb2)
> 
> before running the reshape command, but I'm hoping someone knows a way
> to do the desired reshaping without this step, as it becomes very time  
> consuming with large numbers of repeated measurements.
> 
> Thanks,
> Ista
> 
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