Regular Expression for dd/MM/yyy or dd/MM/yyyy hh:mm:ss

Question

I'll admit I'm rubbish at regular expressions and find some of the tools out there that are supposed to make generating them easier painfully difficult to use. That's my fault granted.. anyway..

Can anyone come up with a single regular expression that will allow both dd/MM/yyyy and/or dd/MM/yyyy hh:mm:ss

Yes, I've Googled for it and searched regexlib.

It would be much appreciated.

Cheers in advance.

UPDATE :

Guys, I obviously considered server side parsing.. I am asking specifically for a regex. I may still fall back on this.

I have also looked at lots of online material including sites that a quick Google brings up, so please don't submit obvious sites as i've tried them and resorted to asking the question here.

UPDATE :

Guys, I'm leaning towards doing it via server side date parsing.. But I would still be curious what the regex would be.

Answer 1

I suggest you to take a look at Regular Expression Matching a Valid Date, Matching a Date in mm/dd/yyyy Format and at RegexLib - Dates and Times.

Answer 2

Here is one

[0-9]{2}/[0-9]{2}/[0-9]{4}( [0-9]{2}:[0-9]{2}:[0-9]{2})?

Edit: improved formatting, thanks Nathan Campos.

Or, eliminating many more invalid values:

[0-3][0-9]/[01][0-9]/[0-2][0-9]{3}( [0-2][0-9]:[0-5][0-9]:[0-5][0-9])?

Answer 3

You're probably better off using DateTime.TryParseExact() for this. It has an overload that allows you to specify multiple possible formats.

Answer 4

You can try out the different suggestions here: http://www.regexr.com/

Answer 5

This should work fine, and does most validation (except for number of days in months):

([0-2][0-9]|3[0-1])/(0[1-9]|1[0-2])/[0-9]{4}( ([0-1][0-9]|2[0-3])(:[0-5][0-9]){2})?

You could add month-wise intelligence to the days, but the RegEx expression for that would look rather hairy.