PHP 显示 XML 日历数据 - 合并日事件

Question

我有以下 XML 文件，无法编辑。

<event>
<id>100</id>
<startdate>24/11/2021</startdate>
<description>Event Test 1</description>
</event>
<event>
<id>101</id>
<startdate>24/11/2021</startdate>
<description>Event Test 2</description>
</event>

然后我使用 simplexml_load_file($url) 将其输出到 PHP 文件中：

  $sxml = simplexml_load_file($url) or die("Error: Cannot create object");
foreach ($sxml->children() as $data)
{
echo "<li><h1>", $data->startdate . "</h1></li>";
echo "<li><h1>", $data->description . "</h1></li>";
}

这给了我如下输出：

24/11/2021
Event Test 1
24/11/2021
Event Test 2

但是，我想按日期合并事件，所以输出如下：

24/11/2021
    Event Test 1
    Event Test 2

如何在不编辑 XML 文件的情况下实现这一点？

谢谢！

Answer 1

由于您正在处理 xml，因此您最好使用 xpath 选择数据。

为了演示，假设您的 xml 如下所示：

<?xml version="1.0" encoding="UTF-8"?>
<doc>    
   <event>
      <id>100</id>
      <startdate>24/11/2021</startdate>
      <description>Event Test 1</description>
   </event>
  <event>
     <event>
      <id>101</id>
      <startdate>24/11/2021</startdate>
      <description>Event Test 2</description>
   </event>
      <id>102</id>
      <startdate>24/12/2021</startdate>
      <description>Event Test 3</description>
   </event>
       <event>
      <id>103</id>
      <startdate>24/12/2021</startdate>
      <description>Event Test 4</description>
   </event>    
</doc>

然后在你的代码中：

#search for all event start dates
$starts = $sxml->xpath('//event/startdate');

#get the unique start dates of these event
$dates = array_unique($starts);

foreach($dates as $date) {     
   echo "<li><h1>{$date}</h1></li>" ."\n";

   #search for all events taking place on each start date
   $expression = "//event/startdate[.='{$date}']";
   $events = $sxml->xpath($expression);
   
   #iterate through these events and find their desription
   foreach ($events as $event){
       echo "\t" , "<li><h1> {$event->xpath('./following-sibling::description')[0]}</h1></li>";
       echo "\n";
   }
   echo "\n";
}

输出：

<li><h1>24/11/2021</h1></li>
    <li><h1> Event Test 1</h1></li>
    <li><h1> Event Test 2</h1></li>

<li><h1>24/12/2021</h1></li>
    <li><h1> Event Test 3</h1></li>
    <li><h1> Event Test 4</h1></li>