<?php

?$students = array(

'2010'=>array('令狐沖',"59"),

'2011'=>array('林平之',"44"),

'2012'=>array('曲洋',"89"),

'2013'=>array('任盈盈',"92"),

'2014'=>array('向問天',"93"),

'2015'=>array('任我行',"87"),

'2016'=>array('沖虛',"58"),

'2017'=>array('方正',"74"),

'2018'=>array('岳不群',"91"),

'2019'=>array('寧中則',"90"),

);//10個學(xué)生的學(xué)號、姓名、分?jǐn)?shù)，用數(shù)組存儲

?

foreach($students as $key=>$val)

{ //使用循環(huán)結(jié)構(gòu)遍歷數(shù)組,獲取學(xué)號?

? ? ?echo $key; //輸出學(xué)號

echo ":";

//循環(huán)輸出姓名和分?jǐn)?shù)

foreach($val as $v)

{

echo $v;?

}

echo "<br />";

}

?>

請問里面的$key $students $v $val都代表著什么？是根據(jù)什么定義的名字