在html表单数组中使用null键

In an html form, it is possible to send data as an array.

<!-- This is an associative array -->
<input name="table[key1]">
<input name="table[key2]">

<!-- This is an index-based array -->
<input name="table[]">
<input name="table[]">

Is it possible to store a value into an associative array, using an empty string as a key?
So that php could access the data with $_POST["table"][null]

null is not an empty string, that would be a '' or a "". However, PHP will convert it to an empty string and use that as a key (Look under Example 1 at https://www.php.net/manual/en/language.types.array.php)

So these are equivalent:

$a = array('' => 'hello');
$b = array(null => 'hello');

From your example, the data would be in $_POST["table"][""]