PHP：嵌套 json 和值提取

Posted 2023-02-24

【中文标题】PHP：嵌套 json 和值提取

【英文标题】：PHP: Nested json and value extraction

【发布时间】：2014-05-16 02:02:17

【问题描述】：

我在下面有这个 json。我正在尝试使用 json_decode 获取值。我得到了一些值，但是我在深度嵌套的值上遇到了麻烦。这是json：

"startAt": 0,
"issue": [

    "id": "51526",
    "fields": 
        "people": [
            
                "name": "bob",
                "emailAddress": "[e-mail]",
                "displayName": "Bob Smith",
            ,
            
                "name": "john",
                "emailAddress": "[e-mail]",
                "displayName": "John Smith",
            
        ],
        "skill": 
            "name": "artist",
            "id": "1"
        
    
,

    "id": "2005",
    "fields": 
        "people": [
            
                "name": "jake",
                "emailAddress": "[e-mail]",
                "displayName": "Jake Smith",
            ,
            
                "name": "frank",
                "emailAddress": "[e-mail]",
                "displayName": "Frank Smith",
            
        ],
        "skill": 
            "name": "writer",
            "id": "2"
        
    

]

我知道我可以通过这样做获得一个价值：

foreach ($decoded_array['issue'][0]['fields']['people'] as $person) 
  echo $person['emailAddress'];

但是，有没有一种简单的方法可以获取 bob、john、jake 和 frank 的所有“电子邮件地址”？

谢谢！

【参考方案1】：

最简单的方法实际上就是循环，但首先在$decoded_array['issue'] 嵌套循环，然后在['people'] 上嵌套循环。将您的地址收集到一个输出数组中。

// Note: this assumes you called json_decode() with the second
// param TRUE to force an associative array..
// $decoded_array = json_decode($input_json, TRUE);

$addresses = array();
foreach ($decoded_array['issue'] as $i) 
  foreach ($i['fields']['people'] as $person) 
    // Append the address onto an output array
    $addresses[] = $person['emailAddress'];
  

// De-dupe them if necessary
$addresses = array_unique($addresses);
print_r($addresses);

// Prints
Array
(
    [0] => [e-mail]
    [1] => [e-mail]
    [2] => [e-mail]
    [3] => [e-mail]
)

如果您不确定结构，除了键名为emailAddress 之外，一个稍微花哨的方法是使用array_walk_recurisve() 遍历数组以查找该键。这将收集名为emailAddress 的所有键，而不仅仅是['people'] 子数组中的那些。

$addresses = array();
// Pass $addresses into the closure by reference so you can write to it
array_walk_recursive($decoded_array, function($value, $key) use (&$addresses) 
  // Find *all keys* called emailAddress
  if ($key == 'emailAddress') 
    $addresses[] = $value;
  
);

【参考方案2】：

试试：

function people($peopleArray, $searchProperty, $forValueArray)
  $fva = array_map('strtolower', $forValuArray);
  foreach($peopleArray as $v)
    $sp = $v[$searchProperty]; $sl = strtolower($sp);
    if(in_array($sl, $fva))
      $q[] = $sp;
    
  
  return isset($q) ? $q : 0;

if($ans = people($decoded_array, 'emailAddress', array('bob', 'john', 'jake', 'frank')))
  print_r($ans);

else
  echo 'no results found';

【参考方案3】：

脚本：

$json = "......"                                          //Your json text. 
$decoded_array = json_decode($json)->'issue';           //Decode Json string
foreach($decoded_array as $issue)                        //Get all Issues
    foreach($issue->'fields'->'people' as $person)   //Get all people
        echo $person->'emailAddress'."<br/>";           //Get person's email
    

输出：

[e-mail] [e-mail] [e-mail] [e-mail]

---

现场示例：

http://codepad.org/R1K0Lysi