我有以下代码：
$string = "zero Or one OR two or three";
print_r(explode("or", $string));
现在，这会导致：
Array ( [0] => zero Or one OR two [1] => three )
但是我想忽略分隔符的大小写，以便它适用于Or、OR、...我的结果是：
Array ( [0] => zero [1] => one [2] => two [3] => three )
我该怎么做？
使用 preg_split（）
$string = "zero Or one OR two or three";
$keywords = preg_split("/or/i", $string);
echo '<pre>';print_r($keywords);echo '</pre>';
输出：
Array
(
[0] => zero
[1] => one
[2] => two
[3] => three
)