st: RE: re: data row transformation for irregular consecutive days

["Nick Cox" <n.j.cox@durham.ac.uk>]

Thanks to Kit for the mention. For some Stata logic on working with
spells, see

SJ-7-2  dm0029  . . . . . . . . . . . . . . Speaking Stata: Identifying
spells
        . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  N.
J. Cox
        Q2/07   SJ 7(2):249--265                                 (no
commands)
        shows how to handle spells with complete control over
        spell specification

Nick 
n.j.cox@durham.ac.uk 

Kit Baum

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

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