如何在不知道是否为数组的情况下遍历JSON属性? [英] how to iterate over JSON property not knowing if it's array or not?

问题描述

我有一个问题，其中API用DEPARTURESEGMENT响应我，有时只包含一个对象，有时又包含一个对象数组.视情况而定，我的foreach循环中似乎需要不同的逻辑.

I have this problem where an API responds to me with DEPARTURESEGMENT sometimes containing only one object, and sometimes containing an array of objects. Depending on which case it is, I seem to need different logics in my foreach-loop.

响应A:

{
  "getdeparturesresult":{
     "departuresegment":[{
        "departure":{
           "location":{
              "@id":"7461018",
              "@x":"12.523958",
              "@y":"57.938402",
              "name":"Noltorps centrum"
           },
           "datetime":"2014-12-04 23:05"
        },
        "direction":"Alingsås station",
        "segmentid":{
           "mot":{
              "@displaytype":"B",
              "@type":"BLT",
              "#text":"Buss"
           },
           "carrier":{
              "name":"Västtrafik",
              "url":"http://www.vasttrafik.se/",
              "id":"279",
              "number":"1"
           }
        }
     },
     {
        "departure":{
           "location":{
              "@id":"7461018",
              "@x":"12.523958",
              "@y":"57.938402",
              "name":"Noltorps centrum"
           },
           "datetime":"2014-12-04 23:05"
        },
        "direction":"Alingsås station",
        "segmentid":{
           "mot":{
              "@displaytype":"B",
              "@type":"BLT",
              "#text":"Buss"
           },
           "carrier":{
              "name":"Västtrafik",
              "url":"http://www.vasttrafik.se/",
              "id":"279",
              "number":"1"
           }
        }
     }
     ]
  }
}

使用此循环:

foreach ($apiData->getdeparturesresult->departuresegment as $m) {

此回复B:

{
  "getdeparturesresult":{
     "departuresegment":{
        "departure":{
           "location":{
              "@id":"7461018",
              "@x":"12.523958",
              "@y":"57.938402",
              "name":"Noltorps centrum"
           },
           "datetime":"2014-12-04 23:05"
        },
        "direction":"Alingsås station",
        "segmentid":{
           "mot":{
              "@displaytype":"B",
              "@type":"BLT",
              "#text":"Buss"
           },
           "carrier":{
              "name":"Västtrafik",
              "url":"http://www.vasttrafik.se/",
              "id":"279",
              "number":"1"
           }
        }
     }
  }
}

需要这样的循环(否则会引发错误):

needs a loop like this (otherwise it throws an error):

foreach ($apiData->getdeparturesresult as $m) {

是否有一种方法可以编写循环故障保护，以判断DEPARTURESEGMENT是对象数组还是仅一个对象(方括号[]是json结构的唯一区别吗?)还是我必须以某种方式进行测试并首先查看DEPARTURESEGMENT是否为数组，并根据结果分配到两个不同的循环?

Is there a way to write the loop failsafe for whether DEPARTURESEGMENT is an array of objects or just one object (the brackets [] is the only difference to the structure of the json right?) or do I have to somehow test and see first whether DEPARTURESEGMENT is an array or not, and dispatch to two different loops depending on the outcome?

推荐答案

您有一些可以帮助您的方法:

You have a few methods that can help you:

• is_array
• is_object
• instanceof //如果收到特定对象
• gettype
• json_decode 第二个参数(如果设置为true)会尝试将json解码为数组

• is_array
• is_object
• instanceof // if you receive specific object
• gettype
• json_decode second parameter, which if is set to true, tries to decode the json as an array

在您的情况下，执行以下操作可能会很好:

In you situation, you would probably be fine by doing the following:

if (is_object($entry)) {
    handleObject($entry);
} elseif (is_array($entry) && count($entry)) {
    foreach ($entry as $e) {
        handleObject($e);
    }
}

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