在PHP中声明数组时使用数组值

Question

I was wondering...is it possible to use a value from an array which is currently being declared? Something like:

$a = array(
    'foo' => 'value',
    'bar' => $a['foo']
);

This is only a simple example. It would be pretty useful doing this, since it frees you from doing extra manipulation after the array declaration.

Answer 1

No, you can't, but you can do something like :

$a = array(
    'foo' => ($val = 'value'),
    'bar' => $val
);