Regex pattern for date format dd.MM.yyyy

Question

Is there any regex pattern storage where I can find patterns like dd.MM.yyyy or maybe you can help me with that?

I'm using data validation with data annotations:

[RegularExpression(@"pattern", ErrorMessage = "incorrect date format")]
public string MyDate { get; set; }

What language are you using? What platform? What are you actually trying to achieve? Please post some code examples so we can help with those. — Oded, Jan 22 '13 at 10:41
Sorry, thought regex is same for all languages. Will add some info now — Sergejs, Jan 22 '13 at 10:45
Regular expressions have different "flavours" they are not uniform (though most of the _basic_ ones are). Can you post _examples_ of inputs and expected results? — Oded, Jan 22 '13 at 10:47
So, you are using ASP.NET MVC? Why do you make `MyDate` a _string_ instead of a `DateTime`? — Oded, Jan 22 '13 at 10:53
I have a reason(when I'm using datetime, I can't replace default validation message if entering something like: "Azzzz" what can't be converted to a datetime) I've asked: http://stackoverflow.com/questions/14397098/mvc3-how-to-define-custom-error-messages-using-annotations — Sergejs, Jan 22 '13 at 10:55
http://stackoverflow.com/questions/4896632/uk-date-regular-expression — Oded, Jan 22 '13 at 10:57

score 0 · Answer 1 · edited Jul 03 '19 at 16:19

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You can always try to use a regex tool, such like 'RegExBuddy' or 'Rad Software Regular Expression Designer'.

But a regular expression you wanted is maybe like this:

\d{2}.\d{2}.\d{4}?

edited Jul 03 '19 at 16:19

Emma

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answered Jan 22 '13 at 10:48

wsplinter

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thanks, but i doubt your pattern will fit. it will accept 99.99.9999. This won't be recognized as a date – Sergejs Jan 22 '13 at 10:49
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You need to escape the `.` otherwise _any_ character will match. – Oded Jan 22 '13 at 10:50

score 0 · Answer 2 · edited Jul 03 '19 at 16:19

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As per ECMAScript specification, a quick answer could be

^(\d{2}).\d{2}.(\d{4})$

edited Jul 03 '19 at 16:19

Emma

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answered Jan 22 '13 at 11:00

Santosh Chauhan

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99.99.9999 won't be a valid date – Sergejs Jan 22 '13 at 11:01
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ALso, you forgot to escape the dots. – Tim Pietzcker Jan 22 '13 at 11:05

score 0 · Answer 3 · edited Jul 03 '19 at 16:19

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You can use something like this:

\d{1,2}\\.\d{1,2}\\.(19\d\d|20\d\d)

edited Jul 03 '19 at 16:19

Emma

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answered Jan 22 '13 at 11:08

Oleg Ignatov

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Sergejs · Answer 4 · 2013-01-22T12:07:27.437

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The pattern that doesn't check for short month and leap year:

string pattern = @"(0[1-9]|[12][0-9]|3[01])\.(0[1-9]|1[012])\.(19|20)\d\d"

edited Jan 22 '13 at 12:07

answered Jan 22 '13 at 11:11

Sergejs

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you're right... :( but i havn't seen regex, that checks months and leap years – Sergejs Jan 22 '13 at 11:24
And that's why using a regex to validate a date is not a good idea. Did you read the post linked to by Oded? – Tim Pietzcker Jan 22 '13 at 11:24
So then use `\d{2}\.\d{2}\.\d{4}` as everybody else has suggested. – Tim Pietzcker Jan 22 '13 at 11:40
yes, but more accurate regex will decrease probability of calling additional server validation method, so will leave the one above. Thanks for your help – Sergejs Jan 22 '13 at 12:05

score 0 · Answer 5 · answered Apr 02 '20 at 20:41

// Each month has a different number of days.
// More over, we have different number of days in February which depends on whether
// the year is a leap year. Here is how to solve this problem:
// 1) if the first digit is even, the second digit must be 0, 4, or 8
// 2) if the first digit is odd, the second digit must be 2 or 6
var pattern = "^([02468][048]|[13579][26])$";

// Deal with months with 31 days
var d1 = @"(3[01]|[012]\d|\d)\.(0?[13578]|10|12)\.\d{4}";
// Deak with months with 30 days
var d2 = @"(30|[012]\d|\d)\.(0?[469]|11)\.\d{4}";
// This portion deals with February 29 in leap years
var d3 = @"29\.(0?2)\.\d{2}([02468][048]|[13579][26])";
// Deal with other days in February
var d4 = @"(2[0-8]|[01]\d|\d)\.(0?2)\.\d{4}";
// Full pattern
var date_pattern = $"^({d1}|{d2}|{d3}|{d4})$";

var dates = new[]
{
    "11.12.2001",
    "15.99.2021",
    "14.01.2010",
    "29.02.2020", //leap year
    "29.02.2019", //not a leap year
    "28.02.2019"
};

foreach (var date in dates)
{
    WriteLine($"Date: {date}, Is match: {Regex.IsMatch(date, date_pattern)}");
}

// Output:
// Date: 11.12.2001, Is match: True
// Date: 15.99.2021, Is match: False
// Date: 14.01.2010, Is match: True
// Date: 29.02.2020, Is match: True
// Date: 29.02.2019, Is match: False
// Date: 28.02.2019, Is match: True

Handling leap years in regex will be tough because of the "years that are a multiple of 4 unless they're a multiple of 100 except when they're a multiple of 400" rule. This returns `true` for `"29.02.1600"`, `"29.02.1700"`, `"29.02.1800"`, `"29.02.1900"`, `"29.02.2000"`, and `"29.02.2100"` even though only 1600 and 2000 were leap years. — Lance U. Matthews, Apr 02 '20 at 21:04

Regex pattern for date format dd.MM.yyyy

5 Answers5