Array_merge特定顺序的两个数组

Question

我有两个数组：

$first = array( 
[0] => '11',
[1] => '22',
[2] => '33'
);

$second = array( 
[0] => '44',
[1] => '55',
[2] => '66',
[3] => '77',
[4] => '88',
[5] => '99'
);

如何合并它们，所以新数组中的第一个对象来自数组1，第二个对象来自数组2，然后再次来自数组1，再次来自数组2等？数组的长度并不总是相同。

赞：

$newarray = array(
[0] => '11',
[1] => '44',
[2] => '22',
[3] => '55',
[4] => '33',
[5] => '66',
[6] => '77',
[7] => '88',
[8] => '99'
);