[EpiData-list] Selection of cases with special digits within a longer variable

In Denmark, we have the unique CPR number consisting of birthdate (ddmmyy) followed by 4 numbers. If I have to select a population born in fx 1940 from a larger epidata-fil, I consider to use the export facility, but then need an observation filter only selecting those born in 1940, which means those numbered 40, in position 5 and 6 in the 10 digit CPR variable. Do anybody have knowledge of a relevant syntax for that?

Yours sincerely

Jes Lindholt Ass. professor, PhD Vascular Research Unit Viborg Hospital, Denmark E-mail: jes.s.lindholt@viborg.rm.dk