Re: st: Re: date format

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

Everyone's right, but there is scope for a little
more explanation.

There is an FAQ at
How do I convert date variables into Stata elapsed dates when the 
numbers run together, like 4151999?
http://www.stata.com/support/faqs/data/dateseq.html

Stata 9 or earlier: Elizabeth recommends -todate- from
SSC. I agree with that as a good solution. As far as I
know, nothing in Stata 10 breaks it. -todate- can handle
several date variables at once, which may be a feature
for some users. Naturally, you could also use a loop over
variables with calls to -date()- in Stata 10.

Stata 10: As Alexandra points out, -date()- can now
handle run-together dates.

There is a variant on her solution. Instead of using
-tostring- for a numeric variable, you can get there
directly with

gen datenew=date(string(dateold), "YMD")

-tostring- is at heart an elaborate wrapper for -string()-.
Its extra bells and whistles can be useful when you need
them, but I can't see much harm in just using -string()-
on the fly.

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

Elizabeth Rainwater
-------------------

There may be a new trick in Stata 10, but in Stata 9 I use the
user-written -todate-, available from SSC (-ssc install todate-). They
syntax is:
todate old_date, gen(new_date) pattern(yyyymmdd) format(%d)

Alexandra Griffiths
-------------------

Just use:

gen datenew=date( dateold, "YMD")
format datenew %td

If your date variable is not a string variable then run this (below)
first to convert it to a string:

tostring datesold, replace

Dan Rodriguez
-------------

Need to convert date format of YYYYMMDD into Stata date format. Does 
anyone have a short do-file to accomplish this?

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