使用PHP在两点之间插入字符串

$original_str = "Hello, World!";
$insert_str = "Beautiful ";
$position = 7;

$new_str = substr($original_str, 0, $position) . $insert_str . substr($original_str, $position);

echo $new_str; // 输出：Hello, Beautiful World!

$original_str = "Hello, World!";
$insert_str = "Beautiful ";
$position = 7;

$new_str = substr_replace($original_str, $insert_str, $position, 0);

echo $new_str; // 输出：Hello, Beautiful World!