Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.
From | Kaspar Dardas <kaspar.dardas@googlemail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | Re: st: re: data row transformation for irregular consecutive days |
Date | Mon, 22 Feb 2010 19:05:36 +0100 |
Hi Kit & Nick, thanks a lot. The solution almost worked. However, for some _spell values I receive too many observations. As you can see the top _spell has three observations (1 1 1), however, there can only be two (1 1). I cannot explain why some dates are "grouped" in the same _spell. Most of them are correct but some are incorrectly grouped. Did I do something wrong? ( I have sorted my data by symbol and date furthermore I have used the below code). symbol days date en _spell _seq _end 3IN 04/02/2010 18297 1 1 1 0 3IN 05/02/2010 18298 2 1 2 0 888 12/05/2006 16933 3 1 3 1 888 15/05/2006 16936 4 2 1 1 888 25/09/2006 17069 5 3 1 0 888 26/09/2006 17070 6 3 2 0 888 27/09/2006 17071 7 3 3 0 888 28/09/2006 17072 8 3 4 1 888 03/10/2006 17077 9 4 1 0 gen date = date(days, "DMY") sort symbol date g en = _n tsset en tsspell date, fcond(D.date>1) bys _spell: g sdate = date if _seq==1 bys _spell: g ndate = date if _end collapse sdays ndays, by(symbol _spell) Thanks, Kaspar 2010/2/22 Kit Baum <baum@bc.edu>: > <> > Kaspar said > > Is there a fast way in Stata 11 to do this data transformation? > > What I have: > symbol days > AAL 04-10-2004 > AAL 10-01-2005 > AAL 11-01-2005 > AAL 12-01-2005 > AAL 01-04-2005 > AAL 04-04-2005 > AAL 06-06-2005 > AAL 07-06-2005 > AAL 08-06-2005 > > What I need: > AAL 04-10-2004 04-10-2004 > AAL 10-01-2005 12-01-2005 > AAL 01-04-2005 01-04-2005 > AAL 04-04-2005 04-04-2005 > AAL 06-06-2005 08-06-2005 > > > g date = date(var2,"DMY") > g en = _n > tsset en > // requires N J Cox -tsspell- from SSC (findit tsspell) > tsspell date, fcond(D.date>1) > bys _spell: g sdate = date if _seq==1 > bys _spell: g ndate = date if _end > l > collapse sdate ndate, by(var1 _spell) > format sdate %td > format ndate %td > l > > > Kit Baum | Boston College Economics & DIW Berlin | http://ideas.repec.org/e/pba1.html > An Introduction to Stata Programming | http://www.stata-press.com/books/isp.html > An Introduction to Modern Econometrics Using Stata | http://www.stata-press.com/books/imeus.html > > > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla.edu/stat/stata/ > * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/