Numbering groups consecutively | SPSS Code Fragments

Let’s suppose that you have a variable that counts how many cases you have in each group.  Now what you need is a variable that consecutively numbers these groups.  Below is the syntax to create the group variable.

data list list / a.
begin data.
1
2
3
1
2
3
4
1
2
3
4
5
6
1
2
1
2
3
end data.

compute #x = #x + 1.
if a ne 1 #x = lag(#x).
compute x = #x.
exe.

list.

    a        x 
 
    1.00     1.00 
    2.00     1.00 
    3.00     1.00 
    1.00     2.00 
    2.00     2.00 
    3.00     2.00 
    4.00     2.00 
    1.00     3.00 
    2.00     3.00 
    3.00     3.00 
    4.00     3.00 
    5.00     3.00 
    6.00     3.00 
    1.00     4.00 
    2.00     4.00 
    1.00     5.00 
    2.00     5.00 
    3.00     5.00 
 
Number of cases read:  18    Number of cases listed:  18