哪种数组语法更有效？

Question

I did not find similar question

1

$form['level1']['level2'][] = array(
    'data' => 'some data',
    'type' => 'some type',
);
//etc

2

 $form = array(
   'level1' => array(
      'level2' => array(
         array(
            'data' => 'some data',
            'type' => 'some type',
         ), 
         //etc
       ),
    ),
 );

Answer 1

This is absolutely microoptimizing...

Test 1: 9.0906839370728
Test 2: 8.5538339614868

But the second is more efficient. For example [] is slower as it first has to check for the last index etc... Also the first has to first check if the array already exists (at every dimension) while in the second case it is clear to PHP that there is a new array.

P.s.: But I don't really know, as the first is less to parse than the second. The parser time I didn't measure... (And I don't suppose that the arrays are now very often recreated?)