JS数组与PHP数组的对比

2021-05-19 12:28

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标签:数组和关联数组   引用类型   关联   var   一个   分类   ===   返回值   array   

一、分类与创建

1:JS的数组都是索引数组,数组是一种特殊的对象,创建数组的方式有两种

//方式一
var arr1 = [‘关羽‘, ‘张飞‘, ‘赵云‘, ‘马超‘, ‘黄忠‘]; 
//方式二
var arr2 = new Array();
arr2[0] = ‘关羽‘;
arr2[1] = ‘张飞‘;
arr2[2] = ‘赵云‘;
arr2[3] = ‘马超‘;
arr2[4] = ‘黄忠‘;

2:PHP数组分为索引数组和关联数组,创建方式也有两种

//方式一(索引数组)
$arr1 = [‘关羽‘, ‘张飞‘, ‘赵云‘, ‘马超‘, ‘黄忠‘]; 
//方式二(关联数组)
$arr2 = array(‘一‘=>‘关羽‘, ‘二‘=>‘张飞‘, ‘三‘=>‘赵云‘, ‘四‘=>‘马超‘, ‘五‘=>‘黄忠‘);

二、JS数组赋值是引用传递,而PHP赋值的是一个副本

var arr1 = [‘关羽‘, ‘张飞‘, ‘赵云‘, ‘马超‘, ‘黄忠‘]; 
var arr2 = [‘关羽‘, ‘张飞‘, ‘赵云‘, ‘马超‘, ‘黄忠‘]; 
alert(arr1 == arr2); //输出false 
$arr1 = array(‘关羽‘, ‘张飞‘, ‘赵云‘, ‘马超‘, ‘黄忠‘);
$arr2 = array(‘关羽‘, ‘张飞‘, ‘赵云‘, ‘马超‘, ‘黄忠‘);
echo $arr1 === $arr2; //输出1

JS 对象常称为引用类型,对象的比较均是引用的比较 ,当它们引用同一基对象时,才相等,而php除了 object 外,

其他类型变量大多在赋值、参数传递、返回值中得到都是它的副本, 很少使用按址传递(引用传递),如下:

$arr1 = array(‘关羽‘, ‘张飞‘, ‘赵云‘, ‘马超‘, ‘黄忠‘);
$arr2 = &$arr1; //引用传递
$arr1[5] = ‘魏延‘;
echo $arr1 === $arr2; //仍然输出1,$arr2随$arr1改变

三、由于JS不支持关联数组,所以PHP中json_encode()只将索引数组转为数组格式,而将关联数组转为对象格式。

$arr1 = array(‘one‘, ‘two‘, ‘three‘, ‘four‘, ‘five‘); 
echo json_encode($arr1);  //索引数组转换为数组格式["one","two","three","four","five"]
$arr2 = array(‘1‘=>‘one‘, ‘2‘=>‘two‘, ‘3‘=>‘three‘, ‘4‘=>‘four‘, ‘5‘=>‘five‘);
echo json_encode($arr2); //关联数组转换为对象格式 {"1":"one","2":"two","3":"three","4":"four","5":"five"}

 

JS数组与PHP数组的对比

标签:数组和关联数组   引用类型   关联   var   一个   分类   ===   返回值   array   

原文地址:https://www.cnblogs.com/splendid/p/9742656.html


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