Using do repeat and count | SPSS Code Fragments

This example uses count to count the number of times 0 appears among
v1–v3 (putting it in z1) and likewise for v4–v6 (putting the count in
z2).  Then, if
z1 is 3, then 9999 is placed in v1–v3 using a do repeat loop. 
The same is done for v4–v6.

data list free
  / v1 to v6.
begin data.
0 0 0 1 0 1
1 1 1 1 1 0
0 1 1 0 0 0
0 0 0 0 0 0
end data.

count z1=v1 to v3 (0).
count z2=v4 to v6 (0).

do repeat x=v1 to v3.
   if z1=3 x=9999.
end repeat.

do repeat x=v4 to v6.
   if z2=3 x=9999.
end repeat.

execute.