问题
I was wondering if somebody could point me to a regex code that validates for this: ####/##/##
Example: 1990/05/25
The second number 0 can only be 0 or 1 and the number 2 and only be 0, 1, 2, or 3. Other than that all other numbers in this set are allowed (0-9).
The code should validate that there is only 9 or 10 characters in total including the slashes.
回答1:
If you only want to validate this format, you can use a regex like...
^\d{1,4}\/[01]?\d\/[0-3]\d$
I tested it a bit on some dates here.
This will match:
1990/01/01
2012/13/34
2013/1/39
9999/0/00
But reject:
23121/32/44
12/05/013
013/000/00
If you want to reject invalid dates as well such as 2013/02/29, you can check out this thread.
回答2:
Try this (edit following Jerry)
[0-2][0-9]{3,3}/[0|1][0-9]/[0-3][0-9]
Mess about with the {a,b} notation to change the length of the general digits, it means between a and b of the preceding expression inclusive. It's unclear in your question where you want the digit flexibility to be.
E.g. to emit 2013/5/29, use
[0-2][0-9]{3,3}/[0|1]{0,1}[0-9]/[0-3][0-9]
回答3:
For all things regex I have found this website to be an invaluable resource. http://www.regular-expressions.info/reference.html
Specifically this page should get you what you need and contains a full explanation of how to go about validating date input format (not value) via Regular Expressions.
http://www.regular-expressions.info/dates.html
^(19|20)\d\d[- /.](0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])$
would match
yyyy-mm-dd
来源：https://stackoverflow.com/questions/16814871/regex-specific-date-format