php写入读取json文件的数组内容

php以json文件形式将数组存入本地并读取打印出来，以下为源码：

// 生成一个PHP数组  
$data = array (   
	0 => array ( "a" => "orange",  
		"b" => "banana",  
		"c" => "apple"  
	),  
	1 => array ( 1,2,3,4,5,6),  
	2 => array ( "first",3 => "second","third")  
);  
  
$data[3]['id']='30';  
$data[3]['content']="php content 31";  

//打印二维数组的内容  
print_r ($data);

// 把PHP数组转成JSON字符串  
$json_string = json_encode($data);  
  
// 写入文件  
if(file_put_contents('test.json', $json_string)){
	print('<br>写入文件成功!<br>');
} else {
	print('<br>写入文件失败!<br>');
}

// 从文件中读取数据到PHP变量  
@$json_string = file_get_contents('test.json'); //行首加@以隐藏错误提示
if($json_string){
	// 把JSON字符串转成PHP数组  
	$data = json_decode($json_string, true);  
	// 打印数组内容  
	print_r($data);  
} else {
	print('<br>json文件不存在.');
}

这是写入本地json文件中的内容

[{"a":"orange","b":"banana","c":"apple"},[1,2,3,4,5,6],{"0":"first","3":"second","4":"third"},{"id":"30","content":"php content 31"}]

浏览器运行显示的内容

Array
(
    [0] => Array
        (
            [a] => orange
            [b] => banana
            [c] => apple
        )

    [1] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 3
            [3] => 4
            [4] => 5
            [5] => 6
        )

    [2] => Array
        (
            [0] => first
            [3] => second
            [4] => third
        )

    [3] => Array
        (
            [id] => 30
            [content] => php content 31
        )

)
写入文件成功!
(
    [0] => Array
        (
            [a] => orange
            [b] => banana
            [c] => apple
        )

    [1] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 3
            [3] => 4
            [4] => 5
            [5] => 6
        )

    [2] => Array
        (
            [0] => first
            [3] => second
            [4] => third
        )

    [3] => Array
        (
            [id] => 30
            [content] => php content 31
        )

)