php多维数组foreach循环

<?php

$bigdata = array(
    "group1"=>array(
        array("name"=>"张三","age"=>13,"sex"=>"男"),
        array("name"=>"李四","age"=>14,"sex"=>"男"),
        array("name"=>"王五","age"=>15,"sex"=>"男")
    ),
    "group2"=>array(
        array("name"=>"赵六","age"=>16,"sex"=>"男"),
        array("name"=>"孙七","age"=>17,"sex"=>"男"),
        array("name"=>"王八","age"=>18,"sex"=>"男")
    ),
    "group3"=>array(
        array("name"=>"张三","age"=>19,"sex"=>"男"),
        array("name"=>"张三","age"=>20,"sex"=>"男"),
        array("name"=>"张三","age"=>21,"sex"=>"男")
    )
);
 
 
foreach ($bigdata as $key => $value) {
    echo "{$key}<br><br>";
    foreach ($value as $key1 => $value1) {
        echo "第".($key1+1)."个同学<br>";
        foreach ($value1 as $key2 => $value2) {
            echo "{$key2}==>{$value2}<br>";
        }
        echo "<br>";
    }
    echo "------------------------<br>";
}
?>

group1

第1个同学
name==>张三
age==>13
sex==>男

第2个同学
name==>李四
age==>14
sex==>男

第3个同学
name==>王五
age==>15
sex==>男

------------------------
group2

第1个同学
name==>赵六
age==>16
sex==>男

第2个同学
name==>孙七
age==>17
sex==>男

第3个同学
name==>王八
age==>18
sex==>男

------------------------
group3

第1个同学
name==>张三
age==>19
sex==>男

第2个同学
name==>张三
age==>20
sex==>男

第3个同学
name==>张三
age==>21
sex==>男

------------------------