Re: st: RE: puzzling "missing" before and after "gen newvar = mdy(a, b, c)"

[Michael McCulloch <mm@pinest.org>]

Thanks Nick; using -todate-, now the missing values are no longer generated.

. todate datedx , gen(datedx2) pattern(yyyymmdd)
. format datedx2 %d

Out of curiosity, I looked back at my previous method, and found that there 
were day and month ==99.

. summarize dx??1
    Variable |       Obs        Mean    Std. Dev.       Min        Max
-------------+--------------------------------------------------------
       dxyr1 |     26806    1990.195    1.958295       1987       1993
       dxmo1 |     26806    7.269828    9.244575          1         99
       dxda1 |     26806    17.66037    15.60529          1         99

I appreciate your help.
Michael

At 01:42 PM 1/11/2007, you wrote:

> summarize dx??1
>
> to see which of the days, months, years variables are
> out of range.
>
> Anyway, why are you doing it this way? Only a few days ago
> a thread you started thrashed out the fact that -todate- from SSC
> should be able to do it in one line.
>
> todate datedx, pattern(yyyymmdd) format(%d) gen(datedx1)
>
> Nick
> n.j.cox@durham.ac.uk
>
> Michael McCulloch
>
> > I've converted a string date (yyyymmdd) to Stata format, using:
> >
> > . * convert datedx to Stata format
> > . tostring datedx, replace
> >          datedx was double now str8
> > . generate str4 dxyr1= substr(datedx,1,4)
> > . generate str2 dxmo1 = substr(datedx,5,6)
> > . generate str2 dxda1 = substr(datedx,7,8)
> > . destring dx*, replace
> >          dxyr1 has all characters numeric; replaced as int
> >          dxmo1 has all characters numeric; replaced as byte
> >          dxda1 has all characters numeric; replaced as byte
> > . gen datedx1 = mdy(dxmo1, dxda1, dxyr1)
> >          (387 missing values generated)
> > . format datedx1 %d
> >
> > However, search for missing values before & after my commands
> > yields nothing:
> > . list datedx if missing(datedx) in 1/10
> >
> > Where might the missing 387 values have originated?
>
> *
> *   For searches and help try:
> *   http://www.stata.com/support/faqs/res/findit.html
> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/

Best wishes,
Michael


____________________________________

Michael McCulloch
Pine Street Clinic
Pine Street Foundation
124 Pine Street, San Anselmo, CA 94960-2674
tel     415.407.1357
fax     415.485.1065
email:  mm@pinest.org
web:    www.pinest.org
        www.pinestreetfoundation.org
        www.medepi.net/meta





*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/