基本JSON解码foreach循环不起作用php答案

【问题标题】：Basic JSON Decode foreach loop not working php基本JSON解码foreach循环不起作用php
【发布时间】：2019-01-05 18:23:31
【问题描述】：

在这个问题上已经做了很长一段时间了，我很困惑为什么使用 foreach 循环不起作用，但我展示的另一种方式确实有效。

我的代码：

$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, "http://maps.googleapis.com/maps/api/geocode/json?address=1%20The%20Strand%20Wellard");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
curl_setopt($ch, CURLOPT_HEADER, FALSE);

curl_setopt($ch, CURLOPT_HTTPHEADER, array(
  "Content-Type: application/json"
));

$response = curl_exec($ch);

$json = json_decode($response, true);

foreach ($json['results'] as $item) {
  foreach ($item['geometry'] as $item2) {
    foreach ($item2['location'] as $item3) {
      echo $item3['lat'];
    }
  }
  echo $item['geometry']['location']['lat'];
}

curl_close($ch);

JSON 数据：https://pastebin.com/JU1wSpsD

为什么echo $item3['lat']; 不起作用但echo $item['geometry']['location']['lat']; 起作用？如果有人可以帮助我理解为什么会这样，那就太好了！

【问题讨论】：

添加json数据。提问。
这些答案都没有解决您的问题吗？

标签： php arrays json curl

【解决方案1】：

看看你从 curl 请求中得到的 json，你正在尝试迭代不是多维的几何图形。

如果几何形状类似，请查看下面的代码

"geometry": [{
        "location": {
          "lat": -32.2630411,
          "lng": 115.8164093
        }],

可以迭代，但是你收到的格式可以这样直接访问。

"geometry": {
            "location": {
              "lat": -32.2630411,
              "lng": 115.8164093
            },
foreach ($json['results'] as $item) {

  echo $item['geometry']['location']['lat'];
  echo $item['geometry']['location']['lng'];
}

以下是您从 curl 获得的 json。

{
  "results": [
    {
      "address_components": [
        {
          "long_name": "1",
          "short_name": "1",
          "types": [
            "street_number"
          ]
        },
        {
          "long_name": "The Strand",
          "short_name": "The Strand",
          "types": [
            "route"
          ]
        },
        {
          "long_name": "Wellard",
          "short_name": "Wellard",
          "types": [
            "locality",
            "political"
          ]
        },
        {
          "long_name": "City of Kwinana",
          "short_name": "Kwinana",
          "types": [
            "administrative_area_level_2",
            "political"
          ]
        },
        {
          "long_name": "Western Australia",
          "short_name": "WA",
          "types": [
            "administrative_area_level_1",
            "political"
          ]
        },
        {
          "long_name": "Australia",
          "short_name": "AU",
          "types": [
            "country",
            "political"
          ]
        },
        {
          "long_name": "6170",
          "short_name": "6170",
          "types": [
            "postal_code"
          ]
        }
      ],
      "formatted_address": "1 The Strand, Wellard WA 6170, Australia",
      "geometry": {
        "location": {
          "lat": -32.2630411,
          "lng": 115.8164093
        },
        "location_type": "ROOFTOP",
        "viewport": {
          "northeast": {
            "lat": -32.2616921197085,
            "lng": 115.8177582802915
          },
          "southwest": {
            "lat": -32.2643900802915,
            "lng": 115.8150603197085
          }
        }
      },
      "place_id": "ChIJTTGvZi2FMioReYR3OgBb-p4",
      "plus_code": {
        "compound_code": "PRP8+QH Wellard, Western Australia, Australia",
        "global_code": "4PVQPRP8+QH"
      },
      "types": [
        "street_address"
      ]
    }
  ],
  "status": "OK"
}

【讨论】：

【解决方案2】：

$json['results'][0]['geometry'] 在 JSON 中是一个对象，而不是一个数组。当你转换它时，你会得到一个带有键'location'、'location_type'和'viewport'的数组：

[geometry] => Array
      (
          [location] => Array
               (
                    [lat] => -32.2630411
                    [lng] => 115.8164093
                )
          [location_type] => ROOFTOP
          [viewport] => Array
              (
                   [northeast] => Array
                       (
                           [lat] => -32.261692119708
                           [lng] => 115.81775828029
                       )
                    [southwest] => Array
                       (
                           [lat] => -32.264390080291
                           [lng] => 115.81506031971
                       )
               )
        )

$item2 然后依次成为这些值，即

Array
    (
         [lat] => -32.2630411
         [lng] => 115.8164093
    )

然后

'ROOFTOP'

然后

Array
    (
         [northeast] => Array
              (
                   [lat] => -32.261692119708
                   [lng] => 115.81775828029
               )
          [southwest] => Array
               (
                   [lat] => -32.264390080291
                   [lng] => 115.81506031971
               )
       )

如您所见，这些数组都没有关键的“位置”，因此$item2['location'] 上的foreach 失败。

但是您可以直接访问$json['results'][0]['geometry']['location']['lat'] 或在您的代码中访问$item['geometry']['location']['lat']

【讨论】：

【解决方案3】：

请先做 var_dump:

echo '<pre style="direction:ltr">';
var_dump($json['results']);
die();

var_dump 结果是：

    array(1) {
  [0]=>
  array(6) {
    ["address_components"]=>
    array(7) {
      [0]=>
      array(3) {
        ["long_name"]=>
        string(1) "1"
        ["short_name"]=>
        string(1) "1"
        ["types"]=>
        array(1) {
          [0]=>
          string(13) "street_number"
        }
      }
      [1]=>
      array(3) {
        ["long_name"]=>
        string(10) "The Strand"
        ["short_name"]=>
        string(10) "The Strand"
        ["types"]=>
        array(1) {
          [0]=>
          string(5) "route"
        }
      }
      [2]=>
      array(3) {
        ["long_name"]=>
        string(7) "Wellard"
        ["short_name"]=>
        string(7) "Wellard"
        ["types"]=>
        array(2) {
          [0]=>
          string(8) "locality"
          [1]=>
          string(9) "political"
        }
      }
      [3]=>
      array(3) {
        ["long_name"]=>
        string(15) "City of Kwinana"
        ["short_name"]=>
        string(7) "Kwinana"
        ["types"]=>
        array(2) {
          [0]=>
          string(27) "administrative_area_level_2"
          [1]=>
          string(9) "political"
        }
      }
      [4]=>
      array(3) {
        ["long_name"]=>
        string(17) "Western Australia"
        ["short_name"]=>
        string(2) "WA"
        ["types"]=>
        array(2) {
          [0]=>
          string(27) "administrative_area_level_1"
          [1]=>
          string(9) "political"
        }
      }
      [5]=>
      array(3) {
        ["long_name"]=>
        string(9) "Australia"
        ["short_name"]=>
        string(2) "AU"
        ["types"]=>
        array(2) {
          [0]=>
          string(7) "country"
          [1]=>
          string(9) "political"
        }
      }
      [6]=>
      array(3) {
        ["long_name"]=>
        string(4) "6170"
        ["short_name"]=>
        string(4) "6170"
        ["types"]=>
        array(1) {
          [0]=>
          string(11) "postal_code"
        }
      }
    }
    ["formatted_address"]=>
    string(40) "1 The Strand, Wellard WA 6170, Australia"
    ["geometry"]=>
    array(3) {
      ["location"]=>
      array(2) {
        ["lat"]=>
        float(-32.2630411)
        ["lng"]=>
        float(115.8164093)
      }
      ["location_type"]=>
      string(7) "ROOFTOP"
      ["viewport"]=>
      array(2) {
        ["northeast"]=>
        array(2) {
          ["lat"]=>
          float(-32.2616921197085)
          ["lng"]=>
          float(115.8177582802915)
        }
        ["southwest"]=>
        array(2) {
          ["lat"]=>
          float(-32.2643900802915)
          ["lng"]=>
          float(115.8150603197085)
        }
      }
    }
    ["place_id"]=>
    string(27) "ChIJTTGvZi2FMioReYR3OgBb-p4"
    ["plus_code"]=>
    array(2) {
      ["compound_code"]=>
      string(45) "PRP8+QH Wellard, Western Australia, Australia"
      ["global_code"]=>
      string(11) "4PVQPRP8+QH"
    }
    ["types"]=>
    array(1) {
      [0]=>
      string(14) "street_address"
    }
  }
}

您必须从结果中获取索引 0：

    echo '<pre style="direction:ltr">';
    var_dump($json['results'][0]['geometry']   ['location']['lat']);
    die();

结果是：float(-32.2630411)

【讨论】：

【解决方案4】：

试试这个，它在这里工作您的代码不起作用，因为您的第一个 foreach 循环将循环一次，因为 $json['results'] 只有一个索引 0，而第二个 foreach 循环将循环三次，因为 $item['geometry'] 有三个索引（位置，location_type，视口）。在第二个 foreach 循环中，您的 $item2 变量将包含来自 (location,location_type,viewport) 的每个索引的值，这意味着您将在此 $item2 变量中获得“纬度”索引。您不需要运行第三个 foreach 循环:)

    <?php 
$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, "http://maps.googleapis.com/maps/api/geocode/json?address=1%20The%20Strand%20Wellard");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
curl_setopt($ch, CURLOPT_HEADER, FALSE);

curl_setopt($ch, CURLOPT_HTTPHEADER, array(
  "Content-Type: application/json"
));

$response = curl_exec($ch);

$json = json_decode($response, true);


foreach ($json['results'] as $item) {

  foreach ($item['geometry'] as $key=>$item2) {

   if($key == 'location')
    echo $item2['lat'];

    }

}

curl_close($ch);

?>

【讨论】：