[R] How to transform: 4 columns into two columns stacked

[(Ted Harding)]

On 16-Jul-10 11:27:18, Ralf B wrote:
> I have the following data structure:
> 
> n=5
> mydata <- data.frame(id=1:n, x=rnorm(n), y=rnorm(n), id=1:n,
> x=rnorm(n), y=rnorm(n))
> print(mydata)
> 
> producing the following represention
> 
> id          x           y id.1       x.1        y.1
> 1  1  0.5326855 -2.07633703    1 0.7930274 -1.0530558
> 2  2  0.7888909  0.63354693    2 0.5908323 -1.3543282
> 3  3  0.5350803 -0.20108931    3 2.5079242 -0.4657274
> 4  4 -1.3041960 -0.25195129    4 1.6294046 -1.4094830
> 5  5  0.3109767 -0.02305981    5 0.5183756  1.3084776
> 
> 
> however I need to transform this data into this form:
> 
>     id          x           y
> 1  1  0.5326855 -2.07633703
> 2  2  0.7888909  0.63354693
> 3  3  0.5350803 -0.20108931
> 4  4 -1.3041960 -0.25195129
> 5  5  0.3109767 -0.02305981
> 6  1 0.7930274 -1.0530558
> 7  2 0.5908323 -1.3543282
> 8  3 2.5079242 -0.4657274
> 9  4 1.6294046 -1.4094830
> 10 5 0.5183756  1.3084776
> 
> what is the simplest way to do that?
> 
> Thanks a lot in advance!
> Ralf

Something on the lines of

  dataframe(id = c(mydata$id, mydata$id1),
            x  = c(mydata$x , mydata$x1 ),
            y  = c(mydata$y , mydata$y1 )

Ted.

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Date: 16-Jul-10                                       Time: 12:56:48
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