I have a table: 
  

      W X Y Z
    A 2 3 4
    A 2 3 6
    B 1 2 3
    C 3 2 1
    B 1 3 4
    B 1 2 2
    
    
    # reproducible data
    table <- read.table(textConnection("W\tX\tY\tZ
                                       A\t2\t3\t4
                                       A\t2\t3\t6
                                       B\t1\t2\t3
                                       C\t3\t2\t1
                                       B\t1\t3\t4
                                       B\t1\t2\t2"), header = TRUE)

I want to combine all rows with same value in Column W, so that it looks like

    W   X  Y     Z
    A   2  3     2,6
    B   1  2,3   3,4,2
    C   3  2     1 

**Note:** All different values of column **W** entries appear as comma separated.
You can also use the `aggregate` function in combination with the `unique` function

    aggregate(table[,2:4], list(table[,1]), function(x) paste0(unique(x)))