When can I combine or separate functions?

[ocon]

I don't know if it's terrible practice or not, but I often combine multiple functions on the same line instead of assigning a variable I'm only going to use once. Normally its not a problem, but I'm getting an "Only variables should be passed by reference" error for:

$name = array_shift(array_values(array_diff($candidates, $conflicts)));

I don't get an error if I break it into two lines:

$vettedCandidates = array_values(array_diff($candidates, $conflicts));
$name = array_shift($vettedCandidates);

I just don't understand what the difference is and why the first one gives me an error. To me, they would seem the same.

[Readie]

array_shift modifies the variable you pass into it.

If you look on the docs [uk3.php.net], it's shown as

array_shift ( array &$array )

- the leading ampersand there means it's a reference rather than a typical variable. A function call cannot be a reference.