用正規表示式替換字串

 placeholderCopy$string = "a;b;c\nd;e;f";
// $1, $2 and $3 represent the first, second and third capturing groups
echo preg_replace("(^([^;]+);([^;]+);([^;]+)$)m", "$3;$2;$1", $string);

輸出

 placeholderCopyc;b;a
f;e;d

搜尋分號之間的所有內容並反轉順序。