PHP Regex to check date is in YYYY-MM-DD format

Question

I'm trying to check that dates entered by end users are in the YYYY-MM-DD. Regex has never been my strong point, I keep getting a false return value for the preg_match() I have setup.

So I'm assuming I have made a mess of the regex, detailed below.

$date="2012-09-12";

if (preg_match("^[0-9]{4}-[0-1][0-9]-[0-3][0-9]$",$date))
    {
        return true;
    }else{
        return false;
    }

Any thoughts?

Answer 1

Try this.

$date="2012-09-12";

if (preg_match("/^[0-9]{4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$/",$date)) {
    return true;
} else {
    return false;
}