Are arrays implicitly created in PHP when one of its keys are assigned something?

问题

Just wishing to quickly verify this. It is different from my immediate experience from other languages whereby an array must first be declared before it can be filled with values.

回答1:

Yes, PHP will automatically create an array given any of the following

$foo[] = $bar;
$foo[1] = $bar;
$foo['bar'] = $bar;

// and of course
$foo = array();

// and soon to pass
$foo = [1, 2, 3];

回答2:

PHP will create the array even without being implicitly declared, yes.

$array[] = ...

$array would be a valid array.

回答3:

$array['one'] = "one". Is this what your asking? Because yes, this will create a new array

来源：https://stackoverflow.com/questions/6853067/are-arrays-implicitly-created-in-php-when-one-of-its-keys-are-assigned-something