R help - Sep 2010 - Moving non-zero matrix entries to different locations on the matrix

I have a matrix:
    C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12
R1   0  0  0  0  0  5  0  0  0   0   0   0
R2   0  0  0  0  0  3  0  0  0   0   0   0
R3   0  0  0  0  0  0  4  0  0   0   0   0
R4   0  0  0  0  0  0  2  0  0   0   0   0
R5   1  0  0  0  0  0  0  0  0   0   0   0
R6   8  0  0  0  0  0  0  0  0   0   0   0
R7   0 15  6  0  3  0  0  0  0   0   0   0
R8   0  9  7 18 17  0  0  0  0   0   0  44
R9   0  0  0 23  0  0  0  0  0   0   0  52
R10  0  0  0  0  0  0  0  0  0   0  19   0
 where most of the entries are zeros. I wish to move some of the non -zero 
entries to locations where there are not as many non-zero entries giving a 
matrix like the one below:

    C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12
R1   0  0  0  0  0  0  0  0  0   0   0   0
R2   0  0  0  0  0  0  0  0  0   0   0   0
R3   0  0  0  0  0  0  0  0  0   0   0   0
R4   0  0  0  0  0  0  0  0  0   0   0   0
R5   0  0  0  0  0  0  0  0  0   0   0   0
R6   0  0  0  0  0  0  0  0  0   0   0   0
R7   1 15  6 18  3  5  4  0  0   0   0  44
R8   8  9  7 23 17  3  2  0  0   0   0  52
R9   0  0  0  0  0  0  0  0  0   0   0   0
R10  0  0  0  0  0  0  0  0  0   0  19   0


R7 and R8 had more non-zero entries than all the other rows so, the non-zero 
entries had to be moved to R7 and R8.

Can any one write a simple function that can implement this idea.
Thanks in advance for your help,
JN



      
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