This regex validates the year 1200-2299.

The regular expression checks for the street numbers or apartment numbers of addresses. It also assumes that the numbers can have a prefix or suffix. Unit/Apartment numbers are of the form Unit Number/Street Number e.g. 10/12.

Regex able to parse iCal to fetch, for example, the schedule of students.

identifying left leading digits and symbols for removal (required for example for cleaning units of measure)