PHP foreach遍历的不仅仅是数组，还可以是对象

foreach (array_expression as $value)   statementforeach (array_expression as $key => $value)   statement

<?php
$arr = array(1, 2, 3, 4,7,8,9,10,11);
foreach($arr as $a)
{    echo $a,'<br/>';//1 2 3 4 5 6 7 8 9 10 11} 
?>

<?php 
$arr = array(1, 2, 3, 4,7,8,9,10,11); 
foreach($arr as $a => $v){    
echo 'key',$a,'== value',$v,'<br/>';}
// key0== value1// key1== value2// key2== value3// key3== value4// key4== value7// key5== value8// key6== value9// key7== value10// key8== value11
?>

//定义类class Man{    
public $name = 'LiLei';    
public $height = 178;    
public $weight = 140;    
protected $age = 30;    
private $money = 1000;}//实例化 $m = new Man();
//遍历
foreach($m as $k => $v)
{    
echo $k . ' : ' . $v . '<br/>';    //$k为属性名，$v为属性值 }
/* name : LiLei   height : 178   weight : 140 */