PHP数组

<?php/*索引数组*//*1.如何创建数组*/$arr = array('zhang', 'li', "wang");$arr_2 = array(    'zhang',    'li',    'wang',);/*2.取出数组值*/echo $arr[0] . '<br>';print_r($arr);var_dump($arr);for ($i = 0; $i < count($arr); $i++) {    echo $arr[$i];    echo '<br>';}//关联数组1.创建$age = array(    "Peter" => "77",    "Ben" => "37",    "Joe" => "43"    );2.取值echo $age['Peter'] . "<br>";foreach ($age as $key => $value) {    echo $key . ":" . $value;    echo "<br>";}foreach ($age as $k) { //一个值代表数值    echo $k;    echo "<br>";}sort($age);foreach ($age as $key => $value) {    echo "age[" . $key . "]:" . $value . "<br>";}3.排序<?php    $fruits = array(        "a" => "orange",         "b" => "banana",         "c" => "apple"    );    asort($fruits);    foreach ($fruits as $key => $val) {        echo "$key = $val\n";}    sort();//升序    asort — 对数组进行排序并保持索引关系;按值排序    ksort — 对数组按照键名排序    rsort();//降序    arsort — 对数组进行逆向排序并保持索引关系    krsort — 对数组按照键名逆向排序*//*键值对(key-value)*/?><script>  //js的写法    //js数组(字面量创建)    var arr = [        'zhang',        'li',        'wang'    ];    var arr_2 = new Array(        'zhang',        'li',        'wang'    )    var l = arr.length;</script>