Correct Regular expressions to match a date

Question

What is the correct regular expression to use to validate a date like. 2009-10-22 or 2009-01-01 etc. Platform PHP

Answer 1

If you can rely on more than a regular expression, an hybrid solution by using Posix functions date() and time() delivered with PHP could look like this:

It's not elegant plus you'll be limited by Unix Epoch time (from January 1 1970 00:00:00 GMT to January 19 2038 03:14:07 GMT), but it's reliable and it's well supported in PHP.