PHP foreach遍历问题

Question

我想学生里，teach_user值输出是老师。而不是老师里输出学生的值。

id pid name
1 0 老师1
2 0 老师2
3 1 学生1
4 1 学生2
5 2 学生3

学生1 teach_user 值里调出 老师1
学生2 teach_user 值里调出 老师1
学生3 teach_user 值里调出 老师2

数组：

Array
(
    [1] => Array
        (
            [id] => 1
            [pid] => 0
            [truename] => 老师1
            [groupid] => 1
            [teach_user] => Array
                (
                )

        )

    [2] => Array
        (
            [id] => 2
            [pid] => 0
            [truename] => 老师2
            [groupid] => 1
            [teach_user] => Array
                (
                )

        )

    [4] => Array
        (
            [id] => 4
            [pid] => 1
            [truename] => 学生1
            [regtime] => 1479318572
            [groupid] => 2
            [teach_user] => Array
                (
                )

        )

    [5] => Array
        (
            [id] => 5
            [pid] => 1
            [truename] => 学生2
            [groupid] => 2
            [teach_user] => Array
                (
                )

        )

    [6] => Array
        (
            [id] => 6
            [pid] => 2
            [username] => ls01
            [truename] => 学生3
            [groupid] => 2
            [teach_user] => Array
                (
                )

        )

想学生循环输出 ，然后老师在teach_user 值里。each_user里的值对应学生pid：

想要效果如下：

[0] => Array
        (
            [id] => 10
            [pid] => 1
            [truename] =>学生1
            [groupid] => 2
            [teach_user] => Array
                (
                    [0] => Array
                        (
                            [id] => 1
                            [pid] => 0
                            [truename] => 老师1
                            [groupid] => 1
                            [teach_user] => Array
                            [teach_user] => Array
                                (
                                )

                        )

                )
[1] => Array
        (
            [id] => 10
            [pid] => 1
            [truename] =>学生2
            [groupid] => 2
            [teach_user] => Array
                (
                    [0] => Array
                        (
                            [id] => 1
                            [pid] => 0
                            [truename] => 老师1
                            [groupid] => 1
                            [teach_user] => Array
                            [teach_user] => Array
                                (
                                )

                        )

                )
 [2] => Array
        (
            [id] => 10
            [pid] => 2
            [truename] =>学生3
            [groupid] => 2
            [teach_user] => Array
                (
                    [0] => Array
                        (
                              [id] => 2
                                [pid] => 0
                                [truename] => 老师2
                                [groupid] => 1
                                [teach_user] => Array
                                    (
                                    )
                                (
                                )

                        )

                )              
         。。。。。
        )

PHP循环写法：

$tree = array();  
foreach($数据库 as $v){  
        $tree[$v['id']] = $v;  
        $tree[$v['id']]['teach_user'] = array();  
}  

foreach($tree as $m=>$n){  
    if($n['tid'] != 0){  
        $tree[$n['tid']]['teach_user'][] = &$tree[$m];
    }
}  

我这样些感觉不对。

Answer 1

不知道我理解的对不对，你是想一次性读取所有数据，每个学生对应的老师信息在学生信息数组里面，（不是所有的老师吧？）

            foreach($all_info as $t_key => $t_info){
                if($t_info['pid']==0){
                    $teacher_info[$t_info['id']] = $t_info;
                    unset($all_info[$t_key]);
                }
            }
            foreach($all_info as $s_key => $s_info){
                if(array_key_exists($s_info['pid'],$teacher_info)){
                    $all_info[$s_key]['teach_user'] = $teacher_info[$s_info['pid']];
                }
            }

小白一个希望可以帮到你

Answer 2

嗯...我简单的看了一下，你的问题应该是学生pid对应老师的ID，然后把老师的数据对应放置在学生数组的teach_user下标中。

1. pid为0的表示为老师，反之不为0的为学生

2. 取出pid不为0的学生数组

3. 根据学生pid取出对应的老师数据放置在学生数组中

---

假设：

$students = array();

foreach ($students as $key => $value) {
    $students[$key]['teach_user'] = //这里根据学生的PID（$value['pid']）查询老师的数据 放置在数组中
}

Answer 3

$studet = [];
$teacher = [];

foreach($teacher as $tKey => $tVal){
    $teacherKeyId[$tVal['id']] = $tVal; //将数组转成以id为键的老师数组   
}
foreach($student as $sKey => $sVal) {
    $student[$sKey]['teach_user'] = $teacherKeyId[$sVal['pid']];
}