Question

Is there any way to write a Regex that can validate one type of delimiter in one date time string only?

For example, 30/04/2010 is correct but 30-04/2010 is incorrect.

I googled and found something about backtrack but I am not very sure how to use it. For example, if i have this regex:

(?P<date>((31(?![\.\-\/\—\ \,\–\-]{1,2}(Feb(ruary)?|Apr(il)?|June?|(Sep(?=\b|t)t?|Nov)(ember)?)))|((30|29)(?![\.\-\/\—\ \,\–\-]{1,2}Feb(ruary)?))|(29(?=[\.\-\/\—\ \,\–\-]{1,2}Feb(ruary)?[\.\-\/\—\ \,\–\-]{1,2}(((1[6-9]|[2-9]\d)(0[48]|[2468][048]|[13579][26])|((16|[2468][048]|[3579][26])00)))))|(0?[1-9])|1\d|2[0-8])[\.\-\/\—\ \,\–\-]{1,2}(Jan(uary)?|Feb(ruary)?|Ma(r(ch)?|y)|Apr(il)?|Ju((ly?)|(ne?))|Aug(ust)?|Oct(ober)?|(Sep(?=\b|t)t?|Nov|Dec)(ember)?)[\.\-\/\—\ \,\–\-]{1,2}((1[6-9]|[2-9]\d)\d{2}))

Then how am I supposed to use backtrack here?

Thank you very much.

Answer 1

Not an answer to your question, but have you considered using strtotime()?

It is a very flexible function able to parse about any english date and time:

Feb 2, 2010
February 2, 2010
02/02/10
4 weeks ago
Next Monday

If a date is unparseable, the function will return false (or -1 prior to PHP 5.1).

There are a few gotchas – I think I remember that when using xx-xx-xxxx notation, it tends to assume an european DD-MM-YYYY date – but all in all, you may fare much better with it than with a regex.