Question

我有以下json文件。

{
"posts": [{
        "by": "johir",
        "post": "Hello Ajax took",
        "likes": 0
    }, {
        "by": "johir",
        "post": "Now Work",
        "likes": 0
    }, {
        "by": "johir",
        "post": "Now Work",
        "likes": 0
    }, {
        "by": "johir",
        "post": "Here we go",
        "likes": 0
    }, {
        "by": "johir",
        "post": "Truely painful",
        "likes": 0
    }, {
        "by": "johir",
        "post": "Hello Ajax 4",
        "likes": 0
    }, {
        "by": "johir",
        "post": "Hello Ajax 2",
        "likes": 0
    }, {
        "by": "johir",
        "post": "Hello Ajax",
        "likes": 0
    }]
}

我想从这个json文件中访问帖子。我编写了以下代码来访问特定帖子并将其更改为其他值：

$inp = file_get_contents('posts.json');
$tempArray = json_decode($inp);
error_log($post);
$tempArray=$tempArray->posts;
$tempArray[2]['post']=" Done";

但它不起作用。有没有替代方法呢？我已经尝试了很多来解决这个问题，但我很困惑为什么这不起作用？

Answer 1

<?php
    $sInFile  = 'in.json';
    $sRaw       = file_get_contents( $sInFile );
    $aInData    = json_decode( $sRaw );
    $aPosts     = $aInData->posts;
    $iCountData = count( $aPosts );
    for( $i = 0; $i < $iCountData; ++$i )
    {
        var_dump( $aPosts[ $i ][ 'by' ] );
        var_dump( $aPosts[ $i ][ 'post' ] );
        var_dump( $aPosts[ $i ][ 'likes' ] );
    }
?>

Answer 2

当你处理json字符串时，理解如何遍历它的简单方法是执行json_decode（）然后转储结果，这样你就可以看到你正在处理的内容，如果你不读原始的JSON数据非常好。

这样做

$inp = '{
"posts": [{
        "by": "johir",
        "post": "Hello Ajax took",
        "likes": 0
    }, {
        "by": "johir",
        "post": "Now Work",
        "likes": 0
    }, {
        "by": "johir",
        "post": "Now Work",
        "likes": 0
    }, {
        "by": "johir",
        "post": "Here we go",
        "likes": 0
    }, {
        "by": "johir",
        "post": "Truely painful",
        "likes": 0
    }, {
        "by": "johir",
        "post": "Hello Ajax 4",
        "likes": 0
    }, {
        "by": "johir",
        "post": "Hello Ajax 2",
        "likes": 0
    }, {
        "by": "johir",
        "post": "Hello Ajax",
        "likes": 0
    }]
}';

$tempArray = json_decode($inp);
print_r($tempArray);

这将输出此

stdClass Object
(
    [posts] => Array
        (
            [0] => stdClass Object
                (
                    [by] => johir
                    [post] => Hello Ajax took
                    [likes] => 0
                )

            [1] => stdClass Object
                (
                    [by] => johir
                    [post] => Now Work
                    [likes] => 0
                )

            [2] => stdClass Object
                (
                    [by] => johir
                    [post] => Now Work
                    [likes] => 0
                )

            [3] => stdClass Object
                (
                    [by] => johir
                    [post] => Here we go
                    [likes] => 0
                )

            [4] => stdClass Object
                (
                    [by] => johir
                    [post] => Truely painful
                    [likes] => 0
                )

            [5] => stdClass Object
                (
                    [by] => johir
                    [post] => Hello Ajax 4
                    [likes] => 0
                )

            [6] => stdClass Object
                (
                    [by] => johir
                    [post] => Hello Ajax 2
                    [likes] => 0
                )

            [7] => stdClass Object
                (
                    [by] => johir
                    [post] => Hello Ajax
                    [likes] => 0
                )

        )

)

所以现在你知道json_decode创建了一个带有一个名为posts的属性的对象，它是一个数组。该数组是其他对象的数组。每个对象都有3个属性，by和post以及likes。

所以现在我们看到$tempArray不是一个非常有用的变量名，所以也许我们应该这样编码：

$inp = file_get_contents('posts.json');
$tempObj = json_decode($inp);

因此，您现在可以对此进行处理以获取所有post值，如下所示：

foreach ( $tempObj->posts as $post ) {
    echo $post->post;
}

或者按照这样的特定值：

echo $tempObj->posts[2]->post;

或设置其中一个值

$tempObj->posts[2]->post = ' Done';

如何访问从php中的json文件解析的关联数组的特定元素？

2 个答案: