st: Selecting within a subset of observations

[Ada Keding <ada.keding@york.ac.uk>]

Dear all,

I am trying to use min/max or similar within a subset of observations.

For example, I have one or more event dates for different identifiers:

ID     EventDate
1      01/03/2011
2      31/01/2011
2      05/09/2011
3      12/03/2011

Now I would like to create a variable that displays the latest event
date within each identifier.

ID     EventDate       LatestEventDate
1      01/03/2011      01/03/2011
2      31/01/2011      05/09/2011
2      05/09/2011      05/09/2011
3      12/03/2011      12/03/2011

I have tried a number of long-winded ways using 'duplicates' but have
not found a solution yet.

Any pointers are much appreciated.

Many thanks,

Ada


Ada Keding
The University of York
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