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# st: Sorry wrong title: Bottom to top[...] is an answer to "Merging 2 variables...."

 From To Subject st: Sorry wrong title: Bottom to top[...] is an answer to "Merging 2 variables...." Date Thu, 15 Apr 2010 13:36:36 +0200

Dear Amy,

Stata date and time functions are somehow confusing at the start but very nice to work with later.

If you have the dates in Stata format (number of days from 1,1, 1960)
you don't have to care about the formats and just can calculate:
Var2date - Var1date = date difference.
You can multiply the date difference by 24*60 to change it into minutes.

********* Now to the time of day
I can't guess what your time vars contain.

You have a string format (str5) so you need to transfer the string vars into numeric vars first.
Example:
Replace Var1time_n = real(Var1time)

I suppose the vars contain elapsed seconds or minutes from midnight.
In this case things are rather easy:

You calculate the difference Var2time - Var1time which might be positive or negative.
Then convert this result into minutes if Var[1/2]time counts other time measures.

Finally add the time difference to the date difference (both in minutes) and you have the total difference.

This is one easy way, there are other functions available in the date and time section but one has to know the exact data specification to use them.

Stefan Gawrich

Dear Statalist users,

I am very much a beginner in Stata, and I have Stata 11.0.  I have read the “help dates” instructional from Stata, but am still confused.  For my project in the Zambian hospital setting, I must calculate the elapsed time in minutes of 2 sets of variables, they are:

Var1date: Date patient departed from the clinic
Var1time: Time patient departed from the clinic

Var2date: Date patient arrived at the hospital
Var2time: Time patient arrived at the hospital

The time variables have type “str5” and format “%5s.”  The date variables have the type “long” and format “%dD_m_Y.”  (I also do not quite understand the meaning of “str5,” “%5s,” and “long.”)

I would like to calculate the time difference (in minutes) between the time the patient left the clinic to when the patient arrived at the hospital.  How would I merge, for example, Var2date and Var2time into “Var2” from which I may subtract Var1 (Var2-Var1 = time transport takes).

Thanks very much for your consideration,
Amy

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