how can I assign serial numbers to observations

[sasphd]

Hello,

In SAS, how can I assign serial numbers to observations organized by group  in a data set. My data set looks like this:

GROUP     OBSNUB

1                    1

1                     2

1                     3

.

.

2                    1

2                    2

2                    3

.

.

3                    1

3                     2

3                     3

3                      4

Thanks

[Reeza · Accepted solution]

SAS FAQ: How can I create an enumeration variable by groups?