Background
In every other programming language I use on a regular basis, it is simple to operate on the return value of a function without declaring
There isn't a way to do that unfortunately, although it is in most other programming languages.
If you really wanted to do a one liner, you could make a function called a() and do something like
$test = a(func(), 1); // second parameter is the key.
But other than that, func()[1] is not supported in PHP.