[R] data manipulation

[Martin Lam]

Hi,

This may not be the best solution, but at least it's
easy to see what i'm doing, assume that your data set
is called "data":

# remove the 4th column
data1 = data[,-4]

# remove the 3rd column
data2 = data[,-3]

# use cbind to add an extra column with only X1 
#elements
data1 = cbind(data1, array("X1", nrow(data1), 1)

# use cbind to add an extra column with only X2
#elements
data2 = cbind(data2, array("X2", nrow(data2), 1)

# use rbind to add them together as rows
data3 = rbind(data1, data2)

# rename the names of the columns
colnames(data3) <- c("ID", "time", "X", "type")

# show output
data3

The only thing I couldn't figure out is how to sort
the data set per row, perhaps someone else could help
us out on this?

Martin

--- Marc Bernard <bernarduse1 at yahoo.fr> wrote:

> Dear All,
>  
> I would be grateful if you can help me. My problem
> is the following:
> I have a data set like:
>  
> ID  time      X1          X2
> 1    1          x111      x211
> 1    2          x112      x212
> 2    1          x121      x221
> 2    2          x122      x222
> 2    3          x123      x223
>  
> where X1 and X2 are 2 covariates and "time" is the
> time of observation and ID indicates the cluster.
>  
> I want to merge the above data by creating a new
> variable  "X" and "type" as follows:
>  
> ID   time    X            type
> 1     1      x111         X1
> 1     2      x112         X1
> 1     1      x211         X2
> 1     2      x212         X2
> 2     1      x121         X1
> 2     2      x122         X1
> 2     3      x123         X1
> 2     1      x221         X2
> 2     2      x222         X2
> 2     3      x223         X2
> 
>  
> Where "type" is a factor variable indicating if the
> observation is related to X1 or X2...
>  
> Many thanks in advance,
>  
> Bernard
> 
> 		
> ---------------------------------
> 
> 
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