Hi I need help constructing the regex expression

I have created one but it works for only some conditions

(([1-9]|1[0-2]):[0-5][0-9]am-([1-9]|1[0-2]):[0-5][0-9]pm) this is the one that I created it works for the 08:00am-12:00pm but if I check for 08:00am-02:00am it does not work.

 Could anyone please help. I would really appreciate the help.

I need it for doing validation in Java

 Thanks in advance.

--Kiran Kumar

I'm a bit confused here.  What exactly is the format you're trying to validate?  One date that can be between 8:00 am and 2:00 pm, or 2 dates separated by a dash?

it is only one date.

Thanks for your reply Let me know if you any more details.

Thanks,

--Kiran Kumar

Ok, here's how I'd go about it.

 1) The minutes do not vary, they are always 0-59, so [0-5][0-9] describes them completely.

2) The valid am times are: 08,09,10,11.  The valid pm times are 12, 01, 02

We can describe the am times with the regex: (0[89]|(1[01])):[0-5][0-9]am

We can describe the pm times with the regex: (((12|01):[0-5][0-9])|02:00)pm

So, the final regex that will validate both is the ORed result of the two regex's above:

^((0[89]|(1[01])):[0-5][0-9]am)|((((12|01):[0-5][0-9])|02:00)pm)$

With a ^ and $ to signify beginning and end of string respectively.

There may be a more efficient way to represent this regex, but this should get you started.

 

 

Ranges, while they can be done, are a really bad application of regex. If you have a range of values and are only selecting one, that's one thing but you are wanting it to understand a range.  You'd be better served using a datetime function to evaluate this.

A regex of this nature will not guarantee a proper range because regexes don't understand time, just text.  If I put in a time 02:00 PM - 08:00AM it isn't going to know the order is wrong (or going backwards)

---

Michael

"In theory, theory and practice are the same. In practice, they are not."
Albert Einstein

Thanks for the replies guys.

I appreciate your help.

Regards,

--Kiran Kumar