1.代码块
<!doctype html><html lang="en"><head><meta charset="UTF-8"><meta name="viewport"content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0"><meta http-equiv="X-UA-Compatible" content="ie=edge"><title>Document</title></head><body><script>let arr = [1,3,4];for (let i=0;i<arr.length;i++) {console.log(arr[i]);}arr.forEach((item,index)=>console.log(item,index));</script></body></html><?php$arr = [1,3,4];$count = count($arr);for ($i=0;$i<$count;$i++) {var_dump($arr[$i]);}foreach ($arr as $k => $v) {var_dump([$k=>$v]);}//结论//for => for,forEach => foreach
效果
