Re: st: how to get age in number of years, months and days

[jose maria pacheco de souza <jmpsouza@usp.br>]

Em 21/10/2012 02:54, Phil Clayton escreveu:
> I've been playing with something like this (beware wrapped lines):
>
> ----------------
> clear
> input str9 d1 str9 d2
> 	24oct1980 19oct2012
> 	30sep1954 5aug1989
> 	31oct1974 10sep2002
> 	31oct1974 30oct2002
> 	31mar1985 30mar1995
> 	29feb2000 28feb2004
> 	29feb2000 1mar2004
> end
>
> gen date1=date(d1, "DMY")
> gen date2=date(d2, "DMY")
> format %td date1 date2
>
> gen years=floor(((ym(year(date2), month(date2)) - ym(year(date1), month(date1))) - (day(date2) < day(date1))) / 12)
> gen months=(ym(year(date2), month(date2)) - ym(year(date1), month(date1))) - (day(date2) < day(date1)) - 12*years
> gen days=date2 - (dofm(mofd(date1) + 12*years + months) + day(date1) - 1)
>
> list
> ----------------
>
> Of course handling leap years and birthdays on 29 Feb is a little arbitrary. The code for calculating age in years is based on Dan Blanchette's code at the end of this page:
> http://www.ats.ucla.edu/stat//stata/modules/dates.htm
>
> I think Nick's approach of calculating years and days is probably better. However, Nick's code seems to fail with the second last set of dates above.
>
> Phil
Phil:
Thank you for your contribution to the thread.
You and Nick helped very much to understand better the subtleties in 
dealing with dates.
josé maria
> Jose Maria Pacheco de Souza
> Professor Titular (aposentado), Professor Senior
> Departamento de Epidemiologia/Faculdade de Saude Publica, USP
> Av. Dr. Arnaldo, 715
> 01246-904  -  S. Paulo/SP - Brasil
> fones (11)3061-7747; (11)3768-8612
> www.fsp.usp.br/~jmpsouza
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