How to convert standard regex to php regex?

Question

After searching on web for validating time as "HH:MM:SS" I found this: Regex pattern for HH:MM:SS time string. but when i put it in my php code i get an error:

preg_match("^(?:(?:([01]?\d|2[0-3]):)?([0-5]?\d):)?([0-5]?\d)$", "12:33:51", $matches);

this is my error message

Warning: preg_match(): No ending delimiter '^' found in db-dataitem.php on line 128

How could I change the pattern string so it can work for PHP?

score 6 · Answer 1 · edited May 23 '17 at 12:33

6

DATETIME SOLUTION

You can validate all your date/time strings with DateTime::createFromFormat:

Function

function isTimeValid($time, $format = 'H:i:s') {
    $dt = DateTime::createFromFormat($format, $time);
    return $dt && $dt->format($format) == $time;
}

This function can be used for all datetime-combination validation. Examples

Example

foreach (['12:30:54', '13:30:65', '00:00:00', '00:70:00'] as $time) {
    echo "Time '$time' is " . (isTimeValid($time) ? "" : "not ") . "valid.\n";
}

Example output

Time '12:30:54' is valid.
Time '13:30:65' is not valid.
Time '00:00:00' is valid.
Time '00:70:00' is not valid.

edited May 23 '17 at 12:33

Community

1
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answered Sep 11 '13 at 12:19

Glavić

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I just love this solution, the right tool, for the right job! Plus I learned something today! – Mike Perrenoud Sep 11 '13 at 12:19
thanks, I voted you, this solved my problem,yet i have to give the mark to the right answer related to the question. – Ehsan Zargar Ershadi Sep 11 '13 at 13:02
@EhsanErshadi: ofc. If you will need other kind of datetime validation, you can use this function. [Examples](http://stackoverflow.com/questions/12322824/php-preg-match-with-working-regex/12323025#12323025). – Glavić Sep 11 '13 at 13:17
@Glavić seems you play a lot with datetime :) +1 – swapnesh Sep 11 '13 at 13:20
@swapnesh: hehe, true ;) I had a lot of DateTime related projects ;) – Glavić Sep 11 '13 at 13:21

score 4 · Accepted Answer · answered Sep 11 '13 at 12:18

You should add a delimiter:

preg_match("/^(?:(?:([01]?\d|2[0-3]):)?([0-5]?\d):)?([0-5]?\d)$/", "12:33:51", $matches);

-in PHP pattern is expected to be delimited from modifiers. That delimiter should be non-alphanumeric.

But (as it was done in another good answer) - it's much better to use proper tool for your problem - i.e. validate timestamp via DateTime API.

How to convert standard regex to php regex?

2 Answers2

DATETIME SOLUTION

Function

Example

Example output