Following this great old post from David Walsh’s post Tweet for Code #2, here is a PHP adaptation for this JavaScript Var Swap tweet:
$b = [$a, $a = $b][0];
Works on PHP 5.4 and up.
I know this is not very practical, for daily work, but it can come handy in a job interview.
♦ ♦ ♦
[Update:June 16, 2016]
In PHP 7.1.x it will finally be possible to use a cleaner swap short-code:
[$a, $b] = [$b, $a];
[/Update]