implode 使用一个字符串将数组变成字符串

         <?php         
        $array = array('lastname', 'email', 'phone');

        $comma_separated = implode(",", $array);
         
        echo $comma_separated; // lastname,email,phone

        var_dump(implode('hello', array())); // string(0) ""
        ?>  

explode — 使用一个字符串分割另一个字符串，返回一个数组

         <?php
        // 示例 1
        $pizza  = "piece1 piece2 piece3 piece4 piece5 piece6";
        $pieces = explode(" ", $pizza);
        echo $pieces[0]; // piece1
        echo $pieces[1]; // piece2
         
        // 示例 2
        $data = "foo:*:1023:1000::/home/foo:/bin/sh";
        list($user, $pass, $uid, $gid, $gecos, $home, $shell) = explode(":", $data);
        echo $user; // foo
        echo $pass; // *
         
        ?>  

这里如果字符串没有任何符号可以进行分割的话，就需要考虑别的方法了

str_split — 将字符串转换为数组

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