獲取屬性

Question

我想使用此代碼從XML文件中獲取屬性：

$xmlFile = "http://weather.aero/dataserver_current/httpparam?dataSource=metars&requestType=retrieve&format=xml&stationString=".$_GET['station']."&hoursBeforeNow=1"; 

$xml = simplexml_load_file($xmlFile); 

這是XML文件：

<response xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XML-Schema-instance" version="1.2" xsi:noNamespaceSchemaLocation="http://weather.aero/schema/metar1_2.xsd"> 
<request_index>29916745</request_index> 
<data_source name="metars"/> 
<request type="retrieve"/> 
<errors/> 
<warnings/> 
<time_taken_ms>2</time_taken_ms> 
<data num_results="1"> 
<METAR> 
<raw_text>EGHH 241850Z 17014KT 9999 BKN006 17/16 Q1000</raw_text> 
<station_id>EGHH</station_id> 
<observation_time>2012-08-24T18:50:00Z</observation_time> 
<latitude>50.78</latitude> 
<longitude>-1.83</longitude> 
<temp_c>17.0</temp_c> 
<dewpoint_c>16.0</dewpoint_c> 
<wind_dir_degrees>170</wind_dir_degrees> 
<wind_speed_kt>14</wind_speed_kt> 
<visibility_statute_mi>6.21</visibility_statute_mi> 
<altim_in_hg>29.52756</altim_in_hg> 
<sky_condition sky_cover="BKN" cloud_base_ft_agl="600"/> 
<flight_category>IFR</flight_category> 
<metar_type>METAR</metar_type> 
<elevation_m>11.0</elevation_m> 
</METAR> 
</data> 
</response> 

現在，我可以提取等信息，但要得到，我使用這個屬性：

<?php foreach ($xml->data->METAR[0]->sky_conditions->attributes() as $sky_cover => $cloud_base_ft_agl){ 

      echo"<tr>"; 
      echo"<td><strong>"; 
      if ($sky_cover == "CAVOK") {echo "Ceiling and Visibility OK";} else {echo $val['sky_cover'];} 
      echo"</strong></td>"; 
      echo"<td><strong>"; 
      if (isset($cloud_base_ft_agl)){echo $cloud_base_ft_agl; } 
      echo"</strong></td>"; 
      echo"</tr>"; 
     }?> 

不過，我發現了錯誤： 警告：main（）[function.main]：節點不再存在於

有關如何解決此問題的任何想法？

Answer 1

sky_conditions不退出不存在。請注意，sky_condition不$xml->data->METAR[0]->sky_conditions->attributes()

這將解決這個問題

$td = "<tr><td><strong>%s</strong></td><td><strong>%s</strong></td></tr>"; 
echo '<table>'; 
foreach ($xml->data->METAR[0]->sky_condition as $value) { 
    $attribute = $value->attributes(); 
    printf($td, $attribute['sky_cover'], $attribute['cloud_base_ft_agl']); 
} 
echo '</table>';