Regex to validate numbers and forward slashes for date

Question

Hi I am trying to wright Regular Expression for date mm/dd/yyyy C#. I have this

^(0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])[- /.](19|20)\d\d$

But it doesn't work
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How to do so it will works with 3/1/2013 and with 03/01/2013

What does "doesn't work" mean? How can we help if you don't even tell us the problem? — tckmn, Mar 22 '13 at 01:32
If i insert date like mm/dd/yyyy it shows that it is in correct — Andrey, Mar 22 '13 at 01:33
When using "or", remember to group units that should stick together with a non capturing group. Your second parenthesised expression is matching zero followed by a number from 1 to 9, or a numbers between 10 and 29 or 3, followed by either of 0 or 1. — Asad Saeeduddin, Mar 22 '13 at 01:34
`3/1/2013` isn't mm/dd/yyyy format. You need to have the zeros there. Or change your regex to make the zeros optional. — Asad Saeeduddin, Mar 22 '13 at 01:37
how to do so it will works with `3/1/2013` and with `03/01/2013`? — Andrey, Mar 22 '13 at 01:38
Make the zeros optional, so `((?:0?[1-9])|(?:1[012]))[- /.]((?:0?[1-9])|(?:[12][0-9])|(?:3[01])).....` — Asad Saeeduddin, Mar 22 '13 at 01:42
Use DateTime.TryParseExact instead. It's got all the logic built in already. — rein, Mar 22 '13 at 01:43

score 7 · Answer 1 · answered Mar 22 '13 at 01:42

7

Don't use regular expressions, use DateTime.TryParse or DateTime.TryParseExact.

Also be aware of the current culture and the user's expectations. Americans use "MM/dd/yyyy" but the rest of the world (generally) uses "dd/MM/yyyy", both are indistinguishable for large ranges of dates.

answered Mar 22 '13 at 01:42

Dai

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app will used only in US and I am using Ajax datatime picker – Andrey Mar 22 '13 at 01:44
Just in case you're using JSON input using MS serialized dates and failing to tryparse the values, try: http://stackoverflow.com/questions/1263732/how-to-pass-a-json-date-value-via-asp-net-mvc-using-json-net – bob-the-destroyer Mar 22 '13 at 01:58

score 2 · Accepted Answer · answered Mar 22 '13 at 01:43

2

I agree that you should use DateTime methods for this. But if you want to make the leading zeros optional you can add a ? after them, like so:

^(0?[1-9]|1[012])[- /.](0?[1-9]|[12][0-9]|3[01])[- /.](19|20)\d\d$

answered Mar 22 '13 at 01:43

Qtax

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Regex to validate numbers and forward slashes for date

2 Answers2