# Re: st: min and max with dates

 From "Sergiy Radyakin" <[email protected]> To [email protected] Subject Re: st: min and max with dates Date Mon, 8 Oct 2007 18:55:29 +0200

```Sorry, Gaby, I was not particularly careful with the syntax, just
wanted to communicate the idea. To be more precise, the resulting
variable is a string, so "min" does not work with it. So, first we
need to:

destring newdate1, generate(nd1)

Now nd1 is a numeric variable. And second, don't write the parenthesis
() after by:

by CODE: egen m=min(nd1)

. l

+----------------+
| CODE   newdate |
|----------------|
1. |   10      0410 |
2. |   10      0414 |
3. |   10      0408 |
4. |   10      0301 |
5. |   20      0208 |
|----------------|
6. |   20      0216 |
7. |   20      0208 |
8. |   20      0210 |
+----------------+

+----------------------------+
| CODE   newdate    nd1  beg |
|----------------------------|
1. |   10      0301   301   301 |
2. |   10      0408   408   301 |
3. |   10      0410   410   301 |
4. |   10      0414   414   301 |
5. |   20      0208   208   208 |
|----------------------------|
6. |   20      0208   208   208 |
7. |   20      0210   210   208 |
8. |   20      0216   216   208 |
+----------------------------+

Best regards,
Sergiy

PS: Nice photos!

On 10/8/07, Ana Gabriela Guerrero Serdan <[email protected]> wrote:
> Dear Sergiy,
>
> Thanks, I managed to swap the month first and then the
> day. But when trying to calculate the minimum it says
>
> by(CODE): egen beg=min(newdate1)
> invalid syntax
> r(198);
>
> I been trying to calculate the mimimum of newdate
> without the sort and its also not possible... !?
> Should I firs set the var as date?
>
>
> Gaby
>
> --- Sergiy Radyakin <[email protected]> wrote:
>
> > Hello Ana Gabriela,
> >
> > this will swap the day and month in the [string]
> > variable Date1:
> > gen newdate1=substr(Date1,3,2)+substr(Date1,1,2)
> > As long as Date2 is always later than Date1, you
> > care only about Date1
> > for the minimum:
> > sort CODE newdate1
> > by(CODE): egen beg=min(newdate1)
> >
> > Quite similarly you proceed to the end dates.
> >
> > Best regards,
> >
> >
> > On 10/8/07, Ana Gabriela Guerrero Serdan
> > <[email protected]> wrote:
> > > Dear all,
> > >
> > > I have a very basic question but I havent find the
> > > date commands when I only have day and month.
> > >
> > > I have information on interviews carried out and
> > want
> > > to know the range of interview per province
> > (CODE), so
> > > I want to calculate the min and max of the dates
> > > within each province.
> > >
> > >
> > > . list  CODE Date1 Date2 Date3
> > >
> > >       +-------------------------------+
> > >       |    CODE   Date1 Date2 Date3   |
> > >       |-------------------------------|
> > >    1. |     01     2704               |
> > >    2. |     01     2704   3004        |
> > >    3. |     01     2704         1505  |
> > >    4. |     01     2505               |
> > >    5. |     01     2605               |
> > >       |-------------------------------|
> > >    6. |     02     2705   0106        |
> > >    7. |     02     2805    0606       |
> > >
> > > etc..
> > >
> > > Can anyone help?
> > >
> > > thanks,
> > > Gaby
> > >
> > >
> > >
> > >
> > >
> >
> ____________________________________________________________________________________
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> >
>
>
> Gaby Guerrero Serdan
>
> Deparment of Economics
> Royal Holloway, University of London
> TW20 OEX
> Egham, Surrey
> England, UK
> http://www.flickr.com/photos/49939890@N00/
>
> Tel: +41788502082 (in switzerland)
>
>
>
> _
>
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```