在创建PHP时将数组值设置为来自同一数组的值

Question

I'm trying to see if you can assign an array value during creation to a value in the same array.

If I'm declaring and initializing an array like this:

$this->array = array(...);

Can I do something like this?

$this->array = array ( 'value1' => 'hello', 'value2' => $this->array['value1'], );

I've tried it already and I get back

Notice: Undefined index: value1 in /Sites/website/config.php on line 329

I've gotten around this problem already but now out of interest I want to see if theres actually a way to do this.

It has to be during creation and declared like above, not through

$array['value1'] = 'foo'; $array['value2'] = $array['value1'];

or

$common = 'foo'; $array = array('value1' => $common, 'value2' => $common);

Is this technically impossible or is there any way?

Answer 1

I don't think it's possible. The array has to be parsed before it can be assigned, so at the time $this->array['value1'] is being calculated, $this->array is still null.

Basically, $this->array['value1'] cannot be be accessed before $this->array['value2'] is set, which needs to access $this->array['value1'], which cannot be accessed before . . .