[EpiData-list] Age Calculation

epidata-list at lists.umanitoba.ca epidata-list at lists.umanitoba.ca
Sat Feb 24 07:57:02 CST 2007

Date variables may be subtracted. So in your example, the correct syntax is:

interval = wdateu - dburthu

Why do you redefine the two dates? Are they <dd/mm/yyyy> in your .qes 
file? The DATE function is for transforming STRING variables in the form 
of dates into date variables (which are stored as number of days since a 
time picked by the EpiData team) That's why subtraction works.

Conversion of one variable type to another is often a challenge. The 
functions that help you do this are explained in the help file (just 
press <F1> and then click on the Functions link). The variable types for 
input and output of functions are shown.


epidata-list at lists.umanitoba.ca wrote:
> *Try.pgm
> cls
> close
> set echo=off
> set replace logfile=on
> read "d:\work\amdate.rec"
> define wdateu <DD/MM/YYYY>
> LET wdateu=wdate
> define dbirthU <DD/MM/YYYY>
> LET dbirthU=dbirth
> define interval ###
> let interval=date("wdateu","dmy")- date("dbirthu","dmy")
> list Interval
> *Error message - (NO RESPONSE)

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