Chuỗi - Cắt chuỗi N ký tự bằng str_split() PHP

<?php
$str = "Hello Friend";
$arr1 = str_split($str);$arr2 = str_split($str, 3);print_r($arr1);print_r($arr2);

?>

Kết Quả : 

Array
(
    [0] => H
    [1] => e
    [2] => l
    [3] => l
    [4] => o
    [5] =>
    [6] => F
    [7] => r
    [8] => i
    [9] => e
    [10] => n
    [11] => d
)

Array
(
    [0] => Hel
    [1] => lo
    [2] => Fri
    [3] => end
)