On 2012-05-31 04:00, epidata-list@lists.umanitoba.ca wrote:

Hello,

I am a relatively new EpiData user and am now using EpiData Analysis.

In EpiData Analysis I would like to create a new variable which will be the number of days between two dates which I have collected in my EpiData dataset. I have started with "define" and the name of the new variable and the new variable will be a numeric variable of length 4. i.e:

define smeartoreg1 ####

However, I am having difficulty with the code for defining the number of days between two existing dates and would appreciate some advice on this. I think I am making a simple mistake that can easily be fixed.

The simple sollution is to make an expression where the two date variable are subtracted from eachother:

smeartoreg1 = datevarend - datevarstart

This will give you the number of days between two dates in the variables.

Here is a small example of how it works - paste this into the Editor of Analysis (F5) and run (F9) then you should see how the date differences are calculated:

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close generate 20 gen d d1 = dmy(1,1,2000) + _n gen d d2 = dmy(1,2,2000) + (_n * 2) gen i daysdiff = d2 - d1 browse

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Kind regards, Torsten Bonde Christiansen EpiData Association.