[R] Split a row vector into columns

[Peter Maclean]

I want to create columns from this row vector. From:
    x1 x2 x3 x1 x2 x3 x1 x2 x3 
     1  2 3  1  2  3  1   2  3

to:
x1 x2 x3
1  2   3
1  2   3
1  2   3 Peter Maclean
Department of Economics
UDSM