一个月的第三个星期四

不是直接的,您需要一个helper函数:

function literalDate($timestamp) {
    $timestamp = is_numeric($timestamp) ? $timestamp : strtotime($timestamp);
    $weekday   = date('l', $timestamp);
    $month     = date('M', $timestamp);   
    $ord       = 0;

    while(date('M', ($timestamp = strtotime('-1 week', $timestamp))) == $month) {
        $ord++;
    }

    $lit = array('first', 'second', 'third', 'fourth', 'fifth');
    return strtolower($lit[$ord].' '.$weekday);
}

echo literalDate('2010-10-21'); // outputs "third thursday"

工作示例:

http://codepad.org/PTWUocx9

strtotime()

 echo date("d.m.Y", strtotime("third thursday", mktime(0,0,0,10,1,2010))); 
 // Will output October 21

 echo date("d.m.Y", strtotime("third thursday", mktime(0,0,0,11,1,2010))); 
 // Will output November 18