可以使用str_split()函数将一个字符串转换为数组。该函数将字符串按照指定的长度拆分为一个数组。例如：
$str = "Hello World";$arr = str_split($str);print_r($arr);输出结果为：
Array( [0] => H [1] => e [2] => l [3] => l [4] => o [5] => [6] => W [7] => o [8] => r [9] => l [10] => d)
