PHP获取数组父级的位置答案

【问题标题】：PHP get the position of a array parentPHP获取数组父级的位置
【发布时间】：2014-03-30 16:30:16
【问题描述】：

这里有一个json字符串，需要获取registratition_id的所有父数组位置例如。我希望最后的数组输出如下内容：

 [0] =>0
 [1] =>1
 [2] =>3

其实我想得到所有包含registration_id的数组位置

$json_raw = '{"multicast_id":6446899316497614986,
                     "success":5,
                     "failure":1,
                     "canonical_ids":3,
                     "results":[
                             {"registration_id":"APA91bEgLFvrc0lnXqX3C1euQohdHrv_wbxtGP86ezRzGWEVMQPpJjw1GMhGzfkI8Q34TU1KRts2j_-7CyU4ce6MlX5DB3umpXDGl-Ebmg53b44UKga79ee9Sal6gT_9rP3KIz9pDEUk2JVJsQmxiWXWoIfrYEAmFg",
                               "message_id":"0:1396175384218906%50b5570df9fd7ecd"
                             },
                             {"registration_id":"APA91bEgLFvrc0lnXqX3C1euQohdHrv_wbxtGP86ezRzGWEVMQPpJjw1GMhGzfkI8Q34TU1KRts2j_-7CyU4ce6MlX5DB3umpXDGl-Ebmg53b44UKga79ee9Sal6gT_9rP3KIz9pDEUk2JVJsQmxiWXWoIfrYEAmFg",
                              "message_id":"0:1396175384218155%50b5570df9fd7ecd"
                             },
                             {"message_id":"0:1396175384218718%b91f4d1ff9fd7ecd"
                             },
                             {"registration_id":"APA91bEgLFvrc0lnXqX3C1euQohdHrv_wbxtGP86ezRzGWEVMQPpJjw1GMhGzfkI8Q34TU1KRts2j_-7CyU4ce6MlX5DB3umpXDGl-Ebmg53b44UKga79ee9Sal6gT_9rP3KIz9pDEUk2JVJsQmxiWXWoIfrYEAmFg",
                              "message_id":"0:1396175384219100%50b5570df9fd7ecd"
                             },
                             {"message_id":"0:1396175384219927%50b5570df9fd7ecd"
                             },
                             {"error":"InvalidRegistration"
                             }]
                       }';

【问题讨论】：

标签： php json multidimensional-array

【解决方案1】：

使用foreach循环并检查registration_id是否isset

$obj = json_decode($json_raw);
$resultsWithRegID = array();

foreach($obj->results as $index=>$element){
  if(isset($element->registration_id)){
     $resultsWithRegID[] = $index;
  }
}

【讨论】：

【解决方案2】：

只是一个替代版本：

$array_raw = json_decode($json_raw, true);

$what = "registration_id";

$res = array_keys(array_filter($array_raw['results'], function($item) use ($what)
{
    return isset($item[$what]);
}));

var_dump($res);

显然你可以：

在isset($item["registration_id"]) 中定义直接搜索的关键字
如果您需要过滤数组的整个部分，请省略包装函数array_keys

(全部)

array (size=3)
    0 => 
        array (size=2)
            'registration_id' => 'APA91bEgLFvrc0lnXqX3C1euQohdHrv...'
            'message_id' => ''
    1 => 
        array (size=2)
            'registration_id' => 'APA91bEgLFvrc0lnXqX3C1euQohdHrv...' 
            'message_id' => '0:1396175384218155%50b5570df9fd7ecd'
    3 =>
        array (size=2)
            'registration_id' => 'APA91bEgLFvrc0lnXqX3C1euQohdHrv...'
            'message_id' => '0:1396175384219100%50b5570df9fd7ecd'

【讨论】：

【解决方案3】：

<html>
<head>
<title>Online PHP Script Execution</title>
</head>
<body>
<?php
  $json_raw = '{"multicast_id":6446899316497614986,
                     "success":5,
                     "failure":1,
                     "canonical_ids":3,
                     "results":[
                             {"registration_id":"APA91bEgLFvrc0lnXqX3C1euQohdHrv_wbxtGP86ezRzGWEVMQPpJjw1GMhGzfkI8Q34TU1KRts2j_-7CyU4ce6MlX5DB3umpXDGl-Ebmg53b44UKga79ee9Sal6gT_9rP3KIz9pDEUk2JVJsQmxiWXWoIfrYEAmFg",
                               "message_id":"0:1396175384218906%50b5570df9fd7ecd"
                             },
                             {"registration_id":"APA91bEgLFvrc0lnXqX3C1euQohdHrv_wbxtGP86ezRzGWEVMQPpJjw1GMhGzfkI8Q34TU1KRts2j_-7CyU4ce6MlX5DB3umpXDGl-Ebmg53b44UKga79ee9Sal6gT_9rP3KIz9pDEUk2JVJsQmxiWXWoIfrYEAmFg",
                              "message_id":"0:1396175384218155%50b5570df9fd7ecd"
                             },
                             {"message_id":"0:1396175384218718%b91f4d1ff9fd7ecd"
                             },
                             {"registration_id":"APA91bEgLFvrc0lnXqX3C1euQohdHrv_wbxtGP86ezRzGWEVMQPpJjw1GMhGzfkI8Q34TU1KRts2j_-7CyU4ce6MlX5DB3umpXDGl-Ebmg53b44UKga79ee9Sal6gT_9rP3KIz9pDEUk2JVJsQmxiWXWoIfrYEAmFg",
                              "message_id":"0:1396175384219100%50b5570df9fd7ecd"
                             },
                             {"message_id":"0:1396175384219927%50b5570df9fd7ecd"
                             },
                             {"error":"InvalidRegistration"
                             }]
                       }';
$data=json_decode ($json_raw);
$arr= $data->{'results'};
$i=0;
$n_r=array();
foreach($arr as $d)
{$n_r[]=$arr[$i]->{'registration_id'};
$i=$i+1;}
print_r($n_r);
?>
</body>
</html>

【讨论】：

【解决方案4】：

将 JSON 转换为数组 - 剩下的就是你的了：

$array = json_decode($json_raw, true);

// results with registration_id
$results = array();
foreach($array['results'] as $index => $element) {
  if(isset($element['registration_id']) === true) {
     $results[] = $index;
  }
}

var_dump($results);

【讨论】：