数据不是XML，而是JSON字符串。
如果可以访问原始XML数据，则可以获得更好的结果。
顺便说一下，要解码当前数据，请使用json_decode：

$data = json_decode($data);

然后，创建一个与countries模式匹配的模式，并匹配$data->CountryList中的所有匹配项

$pattern = '{([^>]+)</Code><Name>([^<]+)</Name></Country>}';
preg_match_all($pattern, $data->CountryList, $matches);

此时，可以通过foreach循环输出<option>列表：

foreach ($matches[0] as $key => $val) {
    echo sprintf('<option value="%s">%s</option>', $matches[1][$key], $matches[2][$key]);
}

• • 一个

编辑：模式语法

{([^<]+)</Code>([^<]+)</Name></Country>}
 └──┬──┘└──┬──┘└──┬──┘└─┬─────────────┘
    │      │      │     └ 2nd and 3rd tags (not captured)
    │      │      └ One or more chars except ‘<’ (2nd captured group)
    │      └ 1st tag (not captured)
    └ One or more chars except ‘<’ (1st captured group)

试试这个，可能对你有帮助。

• • 解决方案**

$json = json_decode($data);$source = new DOMDocument();
$source->loadXml($json->CountryList);
$xpath = new DOMXpath($source);
$target = new DOMDocument();
$options = $target->appendChild($target->createElement('select'));

foreach ($xpath->evaluate('/Countries/Country') as $country) {
    $countryCode = $xpath->evaluate('string(Code)', $country);
    $countryName = $xpath->evaluate('string(Name)', $country);
    $option = $options->appendChild(
        $target->createElement('option')
    );
    $option->setAttribute('value', $countryCode . "|" . $countryName);
    $option->appendChild($target->createTextNode($countryName));
}

$target->formatOutput = TRUE;
echo $target->saveXml($options);

• • 输出：**

<select>
        <option value="AF|Afghanistan">Afghanistan</option>
        <option value="AL|Albania">Albania</option>
        <option value="DZ|Algeria">Algeria</option>
        <option value="AS|American Samoa">American Samoa</option>
        <option value="AD|Andorra">Andorra</option>
        <option value="AO|Angola">Angola</option>
        <option value="AI|Anguilla">Anguilla</option>
        <option value="AQ|Antarctica">Antarctica</option>
        <option value="AG|Antigua & Barbuda">Antigua & Barbuda</option>
        <option value="AR|Argentina">Argentina</option>
        <option value="AM|Armenia">Armenia</option>
        <option value="AW|Aruba">Aruba</option>
        <option value="AU|Australia">Australia</option>
        <option value="AT|Austria">Austria</option>
        <option value="AZ|Azerbaijan">Azerbaijan</option>
        <option value="BS|Bahamas">Bahamas</option>
        <option value="BH|Bahrain">Bahrain</option>
        <option value="BD|Bangladesh">Bangladesh</option>
        <option value="BB|Barbados">Barbados</option>
        <option value="BY|Belarus (Belorussia)">Belarus (Belorussia)</option
     </select>

JSON以XML的形式包含了各个国家，因此必须先对JSON进行解码：

$json = json_decode($data);

然后解析XML：

$source = new DOMDocument();
$source->loadXml($json->CountryList);
$xpath = new DOMXpath($source);

可以使用DOM生成目标XML，创建目标文档并追加根节点，使用Xpath迭代国家并创建/追加选项元素。

$target = new DOMDocument();
$options = $target->appendChild($target->createElement('select'));

foreach ($xpath->evaluate('/Countries/Country') as $country) {
  $option = $options->appendChild(
    $target->createElement('option')
  );
  $option->setAttribute(
    'value', 
    $xpath->evaluate('string(Code)', $country)
  );
  $option->appendChild(
    $target->createTextNode(
      $xpath->evaluate('string(Name)', $country)
    )
  );
}

$target->formatOutput = TRUE;
echo $target->saveXml($options);

输出：

<select>
  <option value="AF">Afghanistan</option>
  <option value="AL">Albania</option>
  <option value="DZ">Algeria</option>
  <option value="AS">American Samoa</option>
  <option value="AD">Andorra</option>
  <option value="AO">Angola</option>
  <option value="AI">Anguilla</option>
  ...