PHP的简写为"if(!isset($ var))$ var = 1;"

Question

是否有简写版本,"如果此变量尚未设置,那么设置它"？

例:

switch ($Frequency) {
    case 'Once':
        doSomethingSpecific();
        break;
    case 'Daily':
        $Message = 'Event will occur every day at the same time.';
    case 'Weekly':
        if (!isset($Message)) $Message = 'Event will occur every week on the same day of the week, at the same time.';
    case 'Monthly':
        if (!isset($Message)) $Message = 'Event will occur every month on the same day of the week.';
        doSomething($Message);
        break;
}

Answer 1

是的,它被称为三元运算符:

$var = isset($var) ? $var : "Some default";

从PHP 5.3开始,还有一个简写版本:

$var = isset($var) ?: "Some default";

PHP 5.3+的替代版本:

isset($var) ?: $var = "Some default";