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Re: st: Sort on time


From   "Sergiy Radyakin" <serjradyakin@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Sort on time
Date   Tue, 11 Nov 2008 13:47:16 -0500

Hugh,

you have two variables date (which shows the date and has 00:00 as
time) and time (which is always Jan1,1960 and proper time). Sorting
first by this variable date, and then by variable time:
   sort date time
will have the same effect as if you combined and reformatted the
variables as others suggested.

Regards, Sergiy


On Tue, Nov 11, 2008 at 1:30 PM, Svend Juul <SJ@soci.au.dk> wrote:
> Hugh wrote:
>
> I have 3 variables; id, date, time.
> "date" and "time" both have a storage type of str8 and are both in %9s
> display format. I need to sort on "id", "date" and "time" in that
> sequence.
>
> I am able to get "date" as float %td, but I am having a problem with
> "time". I got "time" as a double %tc, but it obviously comes out with
> the date "01jan1960" plus the time. I have over 2 million
> observations. I am using Stata 10.
>
> ==========================================================
>
> To make the date and time sortable, combine the two strings into
> one, and next transform the string into a numeric date-and time
> (tc) variable. (It has the numeric value of the number of
> milliseconds (!) since 1 January 1960):
>
>    . clear
>    . set obs 1
>    . gen str sdate = "12112008"
>    . gen str stime = "19:10:00"
>    . gen sdatetime = sdate + " " + stime
>    . gen datetime = clock(sdatetime,"DMY hms")
>    . format datetime %tc
>    . list, clean
>              sdate      stime           sdatetime             datetime
>      1.   12112008   19:10:00   12112008 19:10:00   12nov2008 19:08:55
>
> Hope this helps
> Svend
>
> ________________________________________________________
>
> Svend Juul
> Institut for Folkesundhed, Afdeling for Epidemiologi
> (Institute of Public Health, Department of Epidemiology)
> Vennelyst Boulevard 6
> DK-8000 Aarhus C,  Denmark
> Phone, work:   +45 8942 6090
> Phone, home:   +45 8693 7796
> Fax:           +45 8613 1580
> E-mail:        sj@soci.au.dk
> _________________________________________________________
>
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