ippab wrote:
I have two variables, one indicating date and another indicating time
of the day. For example, date = 03/26/2008 and time = 17:31:30. I am
wondering how I can combine these two variables into one variable so
that I can use the new "Datetime" variable for tis.
My understanding is that 'tis' command (for panel data or time series
analysis) only accepts one variable. Since I have several
observations for a panel on the same day, I need to make sure both
date and time are used as the time variable.
=====================================================
In Stata 10 the numeric value of a date variable is the number of days
since 1 January 1960 , and the numeric value of a time variable is the
number of milliseconds since midnight. Before adding them, transform the
date to milliseconds.
. clear
. set obs 1
. gen date = mdy(3,26,2008)
. format date %tdNN/DD/CCYY
. gen time = hms(17,31,30)
. format time %tcHH:MM:SS
. list
+-----------------------+
| date time |
|-----------------------|
1. | 03/26/2008 17:31:30 |
+-----------------------+
. gen double datetime = date*24*60*60*1000 + time
. format datetime %tcNN/DD/CCYY_HH:MM:SS
. list
+---------------------------------------------+
| date time datetime |
|---------------------------------------------|
1. | 03/26/2008 17:31:30 03/26/2008 17:31:30 |
+---------------------------------------------+
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: [email protected]
_________________________________________________________
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