Question

我有一个API，可以显示我办公室中电表的数据。它总共有四米，而即时取回的值是电流消耗，是不同米的总消耗。

我能够将响应作为JSON检索（我不知道这是否是正确的方法，但是我是API的新手，这是我知道的唯一方法），我可以说它是多维数组，但我不是能够获取单个值。感觉好像很接近，但我无法正常工作。

我正在尝试到达名为“ Meter_Power_2”和“ value”的仪表，但没有。

<?php
    $url = "http://95.209.138.71:12380/api/v1/measurements";
    $data = json_decode(file_get_contents($url), TRUE);
    print_r($data);

?>
<br>

 <?php
    foreach($data as $row){
    echo $row['Meter_2_Power']['Value']."<br>";

    }

?>

当前只是循环浏览所有内容，而没有给我任何回报，因此显然我的循环存在问题。请帮助

编辑：这是完整的响应。

{
  "measurements": [
    {
      "4000_RelayStatus": {
        "Timestamp": "2019-06-21T08:51:06",
        "Value": 0.0
      },
      "Address": "4000"
    },
    {
      "4000_Power": {
        "Timestamp": "2019-06-21T08:51:06",
        "Value": 0.0
      },
      "Address": "4000"
    },
    {
      "4001_RelayStatus": {
        "Timestamp": "2019-06-21T10:15:47",
        "Value": 0.0
      },
      "Address": "4001"
    },
    {
      "4001_Power": {
        "Timestamp": "2019-06-21T10:15:47",
        "Value": 0.0
      },
      "Address": "4001"
    },
    {
      "1200_RelayStatus": {
        "Timestamp": "2018-04-23T12:04:14",
        "Value": 0.0
      },
      "Address": "1200"
    },
    {
      "1200_Power": {
        "Timestamp": "2018-04-23T12:04:14",
        "Value": 0.0
      },
      "Address": "1200"
    },
    {
      "1100_RelayStatus": {
        "Timestamp": "2018-03-28T15:56:49",
        "Value": 0.0
      },
      "Address": "1100"
    },
    {
      "1100_Power": {
        "Timestamp": "2018-03-28T15:56:49",
        "Value": 0.0
      },
      "Address": "1100"
    },
    {
      "3000_RelayStatus": {
        "Timestamp": "2018-03-27T20:13:18",
        "Value": 0.0
      },
      "Address": "3000"
    },
    {
      "3000_Power": {
        "Timestamp": "2018-03-27T20:13:18",
        "Value": 0.0
      },
      "Address": "3000"
    },
    {
      "3500_RelayStatus": {
        "Timestamp": "2018-04-25T11:19:54",
        "Value": 0.0
      },
      "Address": "3500"
    },
    {
      "3500_Power": {
        "Timestamp": "2018-04-25T11:19:54",
        "Value": 0.0
      },
      "Address": "3500"
    },
    {
      "2500_RelayStatus": {
        "Timestamp": "2018-04-25T16:30:35",
        "Value": 0.0
      },
      "Address": "2500"
    },
    {
      "2500_Power": {
        "Timestamp": "2018-04-25T16:30:36",
        "Value": 0.0
      },
      "Address": "2500"
    },
    {
      "Address": "2600",
      "Meter_1_Power": {
        "Timestamp": "2019-06-21T11:44:42",
        "Value": 2694.54
      }
    },
    {
      "Address": "2600",
      "Meter_2_Power": {
        "Timestamp": "2019-06-21T11:43:59",
        "Value": 48.89
      }
    },
    {
      "Address": "2600",
      "Meter_1_Total": {
        "Timestamp": "2019-06-21T11:43:40",
        "Value": 21716.08
      }
    },
    {
      "Address": "2600",
      "Meter_2_Total": {
        "Timestamp": "2019-06-21T11:29:27",
        "Value": 1378.03
      }
    },
    {
      "Address": "2500",
      "Meter_4_Power": {
        "Timestamp": "2019-06-21T11:44:58",
        "Value": 43.22
      }
    },
    {
      "Address": "2500",
      "Meter_3_Power": {
        "Timestamp": "2019-06-21T11:44:58",
        "Value": 3508.51
      }
    },
    {
      "Address": "2500",
      "Meter_4_Total": {
        "Timestamp": "2019-06-21T11:38:16",
        "Value": 966.34
      }
    },
    {
      "Address": "2500",
      "Meter_3_Total": {
        "Timestamp": "2019-06-21T11:43:19",
        "Value": 39735.44
      }
    },
    {
      "2600_RelayStatus": {
        "Timestamp": "2018-04-25T16:20:51",
        "Value": 0.0
      },
      "Address": "2600"
    },
    {
      "2600_Power": {
        "Timestamp": "2018-04-25T16:20:51",
        "Value": 0.0
      },
      "Address": "2600"
    }
  ],
  "result": "OK"
}

Answer 1

这是摘要，

foreach ($arr as $key => $value) {
    if (is_array($value)) {
        foreach ($value as $value1) {
            if (!empty($value1['Meter_2_Power']['Value'])) {
                echo $value1['Meter_2_Power']['Value'] . '<br/>';
            }
        }
    }
}

如果您不考虑对编码进行硬编码，

foreach ($arr['measurements'] as $key => $value) {
    if (!empty($value['Meter_2_Power']['Value'])) {
        echo $value['Meter_2_Power']['Value'] . "\n";
    }
}

AND

array_walk($arr['measurements'], function($value, $key){
    if (!empty($value['Meter_2_Power']['Value'])) {
        echo $value['Meter_2_Power']['Value'] . "\n";
    }
});

Answer 2

您可以尝试以下一种简单方法：

<?php
    $url = "http://95.209.138.71:12380/api/v1/measurements";
    $data = json_decode(file_get_contents($url), TRUE);
?>
<br>

 <?php
    foreach($data['measurements'] as $row){
        if(isset($row['Meter_2_Power'])) echo $row['Meter_2_Power']['Value']."<br>";
    }

?>

从多维数组PHP

2 个答案: