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# st: AW: Merging 2 variables to calculate time elapse (time/date)

 From To Subject st: AW: Merging 2 variables to calculate time elapse (time/date) Date Thu, 15 Apr 2010 15:01:54 +0200

```Var2date: Date patient arrived at the hospital, example: 13 Nov 09
Var2time: Time patient arrived at the hospital, example: 02:32

In this case the patient departed before he/she arrived.
But I suppose that's just a typo.

Try this formula:
This is just a simple calculation without any date or time functions

gen hosptime = (Var2date - Var1date) * 24 * 60 + ///
(real(substr(Var2time,1,2)) - real(substr(Var1time,1,2))) * 60 ///
+ real(substr(Var2time,4,2)) - real(substr(Var1time,4,2))

1. line: Date difference calculated in minutes
2. line: added: difference in whole hours from time variables converted to minutes
3. line: added: difference in minutes from time variable

In the long run working with date and time functions is favourable.

Stefan

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