In the same spirit, the third line should
also be corrected.
gen daysinyear = doy(mdy(12,31,year))
The leap year question is discussed in a FAQ.
FAQ . . . . . . . . . . . . . . . . . . . . . . . . . Leap year indicators
1/04 How do I identify leap years in Stata?
http://www.stata.com/support/faqs/data/leapyear.html
shows that there are lots of ways of checking for a leap year. They
are all at least a little fiddly, but not challenging in principle. My favourite
is that
doy(12,31,year) == 366
is 1 or true for a leap year and 0 or false otherwise. Depending
on details, you may need to plug something into the "year"
slot. On the whole, there is little need to -generate- a variable
for this, at least in my experience. You do need a logical expression
as part of some argument.
I don't think this really is "frequently asked" or "frequently answered",
but it seemed worth writing up.
On the original, I still can't see a consistent interpretation
for the fractional part of
1932.2880
1949.0410
1939.4270
Thus if .288 means 28 August, what does .427 mean?
If .288 means day of year 288, same question!
Nick
[email protected]
Jeph Herrin
> Oops, that third line should be reversed or even simplified:
>
> gen daysinyear=doy(12,31,year)
>
> the point being that Stata doesn't have (as far as I know)
> a function for identifying leap years, though it shouldn't
> be difficult to write one I suppose.
Jeph Herrin
> > If your variable is -date-, the only tricky part is getting
> > the number of days in the year. Try:
> >
> > gen year = round(date,0)
> > gen daysinyear=mdy(1,1,year)-mdy(12,31,year)
> > gen day = round((date-year)*daysinyear,0)
> > gen newdate=mdy(1,1,year)+day
> >
> > Then -newdate- should contain the date in Stata's elapsed
> date format.
Caleb Southworth
>> How can decimal years be read into stata? The data are
> %9.4f and identify
> >> year, month and day, for example
> >>
> >> event1
> >> 1932.2880
> >> 1949.0410
> >> 1939.4270
> >>
> >> I would like to be able to extract the mdy and to be able
> to tsset my
> >> data, the latter requiring integers.
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