That is a great regex. Have you ever complted the full ISO 8601 regex, with intervals, durations, repeat periods?

If you have, it would be very useful for a StratML Specification Schema.

Thank you.

Regards,
Andre

Here are some strings that should match as valid:

2010-02-18T16:23:48.5
2010-02-18T16:23:48,444
2010-02-18T16:23:48,3-06:00
2010-02-18T16:23.4
2010-02-18T16:23,25
2010-02-18T16:23.33+0600
2010-02-18T16.23334444
2010-02-18T16,2283
2009-05-19 143922.500
2009-05-19 1439,55

And here are some strings that should not match as valid:

2009-05-19 146922.500
2010-02-18T16.5:23.35:48
2010-02-18T16:23.35:48
2010-02-18T16:23.35:48.45
2009-05-19 14.5.44
2010-02-18T16:23.33.600
2010-02-18T16,25:23:48,444

Here’s the updated regex that I was able to come up with:

^([\+-]?\d{4}(?!\d{2}\b))((-?)((0[1-9]|1[0-2])(\3([12]\d|0[1-9]|3[01]))?|W([0-4]\d|5[0-2])(-?[1-7])?|(00[1-9]|0[1-9]\d|[12]\d{2}|3([0-5]\d|6[1-6])))([T\s]((([01]\d|2[0-3])((:?)[0-5]\d)?|24\:?00)([\.,]\d+(?!:))?)?(\17[0-5]\d([\.,]\d+)?)?([zZ]|([\+-])([01]\d|2[0-3]):?([0-5]\d)?)?)?)?$

It still doesn’t account for the duration or time interval part of the ISO 8601 spec, so I guess that’ll have to come at a later date.

Lemme know if you find any bugs.

And the following three false negatives you provided are also bugs:

2009
2009-05
2007-04-05T24:00

The other false negatives you listed are indeed valid ISO 8601 date strings. But the W3C recommendation excludes the day-of-year and week-of-year notation from the XML standard.
http://www.w3.org/TR/NOTE-datetime

So your expression is much better for strict compliance with ISO 8601. For compliance with XML, we’ll need something a little different. But either way, it’s time to update this page!

2009-05-19T14a39r
2009-05-19T14:3924
2009-0519
2009-05-1914:39
2009-05-19r14:39
2009-05-19 14a39a22
200912-01

And here are some valid ISO 8601 dates that it should match on but doesn’t:

2009
2009-12T12:34
2009123
2009-05
2009-123
2009-222
2009-001
2009-W01-1
2009-W51-1
2009-W511
2009W511
2009-05-19 14
2009-W21-2
2009-139
2007-04-05T24:00

(Note that 24:00 is a valid representation of midnight according to ISO 8601, so I changed that.) Obviously, this doesn’t include the duration or time interval aspects of ISO 8601 (I left those out because I didn’t need them).

This is the modified regex I came up with:

^([\+-]?\d{4}(?!\d{2}\b))((-?)((0[1-9]|1[0-2])(\3([12]\d|0[1-9]|3[01]))?|W([0-4]\d|5[0-2])-?[1-7]|(00[1-9]|0[1-9]\d|[12]\d{2}|3([0-5]\d|6[1-6])))([T\s](([01]\d|2[0-3])((:?)[0-5]\d)?|24\:?00)?(\15([0-5]\d))?([zZ]|([\+-])([01]\d|2[0-3]):?([0-5]\d)?)?)?)?$

I’d love to hear your input.