regular expression that matches the time without the am/pm

[kee2ka4]

Hey Guys,

 

I am a php newbie and need some help to define a regular express rule that would match the time without the am/pm, so the following formates are all true:

 

9:00

09:00

22:30

23:59

00:00 etc

 

Any directions here...

 

Thanks,

Ket

[Psycho]

When needing a validation such as this, it is very important to have explicit, definitive rules. You gave a few examples of what should pass, but it is not enough. The easy approach would be to validate that the string starts with one or two numbers, has a colon, and then has two more numbers. But, that means 25:01 or 10:99 would pass. Is that acceptable? I don't know your situation. Also, if 00:00 is valid is 24:00 valid as well?

 

Here is one possible solution:

function validTimeStr($timeStr)
{
    return (preg_match("/^((\d|[0-1]\d|2[1-3]):[0-5]\d)|24:00$/", $timeStr)>0);
}

 

Output of tests:

00:00: true
1:25: true
01:25: true
001:25: false
11:59: true
2:64: false
23:23: true
24:00: true
24:01: false

 

You should test against anything else you think might be problematic.

[kee2ka4]

thanks for your reply! The regex rule you defined its fine but without the ":" right at the end. I just need to validate the correct format of HH:MM so 24:00 or 00:00 both are correct time values.

 

Thanks,

K

[Psycho]

The regex rule you defined its fine but without the ":" right at the end.

 

The ":" at the end was just part of my unit test code couput. It has nothing to do with the function. The function will simply return true/false based upon whether the passed value matches the pattern.

[ZachMEdwards]

I'd try a pattern like this:

'/^(0{0,1}[1-9]|1\d|2[0-3])[0-5]\d)$/'

[Psycho]

I'd try a pattern like this:

'/^(0{0,1}[1-9]|1\d|2[0-3])[0-5]\d)$/'

 

That won't work for 24:00 as requirested by the OP. Although, I do see I had an error in my original code for the hour "20". And, that does give me an idea on shortening the original pattern to:

return (preg_match("/^(([0-1]?\d|2[0-3]):[0-5]\d)|24:00$/", $timeStr)>0);

 

- not tested