问题
Is there a shorthand way to assign a variable to something if it doesn't exist in PHP?
if(!isset($var) {
$var = "";
}
I'd like to do something like
$var = $var | "";
回答1:
Update for PHP 7 (thanks shock_gone_wild)
PHP 7 introduces the so called null coalescing operator which simplifies the below statements to:
$var = $var ?? "default";
Before PHP 7
No, there is no special operator or special syntax for this. However, you could use the ternary operator:
$var = isset($var) ? $var : "default";
Or like this:
isset($var) ?: $var = 'default';
回答2:
You can use new ternary operator (PHP 5.3+)
isset($var) ?: $var = "";
Or for older version :
$var = isset($var) ? $var : "";
来源：https://stackoverflow.com/questions/18603250/php-shorthand-for-isset