Statalist


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: st: Sort on time


From   Svend Juul <SJ@SOCI.AU.DK>
To   <statalist@hsphsun2.harvard.edu>
Subject   Re: st: Sort on time
Date   Tue, 11 Nov 2008 19:30:31 +0100

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 
_________________________________________________________ 

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/



© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index