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rstatisticsreformatting

How can I reformat a table in R?

I loaded a table like this:

    V1  V2   V3
  pat1   1    2
  pat1   3    1
  pat1   4    2
  pat2   3    3
  pat3   1    4
  pat3   2    3

and I need to format it into something like the following, with V1 indicating the row, V2 indicating the column, and the values in V3: 

         1    2    3    4
 pat1    2    0    1    2
 pat2    0    0    3    0
 pat3    4    3    0    0

Please, note that pat1 vs. pat2 vs. pat3 have different numbers of observations and that missing values must be filled with 0.

Solution

  • Using dcast from reshape2 :

    library(reshape2)
dcast(dat,V1~V2,fill=0)

    V1 1 2 3 4
1 pat1 2 0 1 2
2 pat2 0 0 3 0
3 pat3 4 3 0 0

    Where dat is : 

    dat <- read.table(text='V1  V2   V3
  pat1   1    2
  pat1   3    1
  pat1   4    2
  pat2   3    3
  pat3   1    4
  pat3   2    3',header=TRUE)