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From | James Bernard <jamesstatalist@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | st: indexing for first non-missing value |
Date | Wed, 15 May 2013 19:46:09 +0800 |
Hi all, I have been dealing with a dataset where I need to copy the value of the first non-missing value of one variable to create a new variable called first year observed: id year first year observed ------- ------------ ----------------------------- A . 1996 A 1996 1996 A 1997 1996 A 1998 1996 A . 1996 A . 1996 B 1998 1998 B 1999 1998 B . 1998 B . 1998 Going through Stata discussions, I found out that one way is to use indexing bysort id: gen first_year_observed=year[1] where the bracket indicates the first non-missing value But this find only the first value, be it missing or non-missing. Is there any simple indexing way? Thanks, James * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/