如何在PHP中获取JSON中的所有密钥？

问题描述：

How do I get all of the keys and loop through them, echoing each one, from a JSON object array?

Here is my code:

/* SAMPLE JSON THAT IS SENT
$mystring = '{
    "display_name": "Silverware",
    "fields": [
        {
            "field_name": "Age",
            "sort_order": 1,
            "required": 0,
            "view_type": "text",
            "description": "",
            "multi_value": 0,
            "char_count": 255
        },
        {
            "field_name": "Brand",
            "sort_order": 2,
            "required": 0,
            "view_type": "multiselect",
            "description": "",
            "multi_value": 1,
            "char_count": 255
        }
    ]
}';
*/


$json = json_decode($HTTP_RAW_POST_DATA);
$arr = $json->{'fields'};

// This is how I print a specific value
//print $arr[0]->{'field_name'};

Adding the following isn't working for me:

foreach ($arr as $k => $v) {
    echo $k', ';
}

如何从JSON对象数组中获取所有键并循环遍历每个键，并回显每个键？

  / * SAMPLE JSON SENT 
 $ mystring ='{
“display_name”：“  Silverware“，
”字段“：[
 {
”field_name“：”Age“，
”sort_order“：1，
”required“：0，
”view_type“：”text“，\  n“description”：“”，
“multi_value”：0，
“char_count”：255 
}，
 {
“field_name”：“Brand”，
“sort_order”：2，
  “required”：0，
“view_type”：“multiselect”，
“description”：“”，
“multi_value”：1，
“
”“char_count”：255 
} 
] 
}'  ; 
 * / 
 
 
 $ json = json_decode（$ HTTP_RAW_POST_DATA）; 
 $ arr = $ json-＆gt; {'fields'}; 
 
 //这是我打印特定值的方式 
 // print $ arr [0]  - ＆gt; {'field_name'}; 
  code>  pre> 
 
 添加以下isn' 为我工作： p> 
 
 
  foreach（$ arr as $ k =＆gt;  $ v）{
 echo $ k'，'; 
} 
  code>  pre> 
  div>

答

Use true for the second parameter of json_decode().

foreach ($j['fields'] as $field) {
  $keys = array_keys($field);
  foreach ($keys as $key) {
    echo $key;
  }
}

如何在PHP中获取JSON中的所有密钥？

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