我是 xml 解析和 xpath 的新手。我需要制作一个可以找到记录标签名称的解析器。例如，如果给定这个 xml ：
<?xml version="1.0" encoding="ISO-8859-1"?>
<items>
<item>
<name>first item</name>
<description>first item description</description>
</item>
<item>
<name>second item</name>
<description>second item description</description>
</item>
</items>
脚本应该能够确定“item”是我正在寻找的标签名称，而无需在代码中的某处指定它。对我来说，每个“item”元素都是一条记录；给定 xml 的示例响应将是“找到 2 个项目”。
这可以用 xpath 和 php 完成吗？
我正在为我的解析器使用 xmlreader。
您可以使用此库将 xml 转换为 php 数组
function xml2array($contents, $get_attributes=1, $priority = 'tag') {
if(!$contents) return array();
if(!function_exists('xml_parser_create')) {
//print "'xml_parser_create()' function not found!";
return array();
}
//Get the XML parser of PHP - PHP must have this module for the parser to work
$parser = xml_parser_create('');
xml_parser_set_option($parser, XML_OPTION_TARGET_ENCODING, "UTF-8"); # http://minutillo.com/steve/weblog/2004/6/17/php-xml-and-character-encodings-a-tale-of-sadness-rage-and-data-loss
xml_parser_set_option($parser, XML_OPTION_CASE_FOLDING, 0);
xml_parser_set_option($parser, XML_OPTION_SKIP_WHITE, 1);
xml_parse_into_struct($parser, trim($contents), $xml_values);
xml_parser_free($parser);
if(!$xml_values) return;//Hmm...
//Initializations
$xml_array = array();
$parents = array();
$opened_tags = array();
$arr = array();
$current = &$xml_array; //Refference
//Go through the tags.
$repeated_tag_index = array();//Multiple tags with same name will be turned into an array
foreach($xml_values as $data) {
unset($attributes,$value);//Remove existing values, or there will be trouble
//This command will extract these variables into the foreach scope
// tag(string), type(string), level(int), attributes(array).
extract($data);//We could use the array by itself, but this cooler.
$result = array();
$attributes_data = array();
if(isset($value)) {
if($priority == 'tag') $result = $value;
else $result['value'] = $value; //Put the value in a assoc array if we are in the 'Attribute' mode
}
//Set the attributes too.
if(isset($attributes) and $get_attributes) {
foreach($attributes as $attr => $val) {
if($priority == 'tag') $attributes_data[$attr] = $val;
else $result['attr'][$attr] = $val; //Set all the attributes in a array called 'attr'
}
}
//See tag status and do the needed.
if($type == "open") {//The starting of the tag '<tag>'
$parent[$level-1] = &$current;
if(!is_array($current) or (!in_array($tag, array_keys($current)))) { //Insert New tag
$current[$tag] = $result;
if($attributes_data) $current[$tag. '_attr'] = $attributes_data;
$repeated_tag_index[$tag.'_'.$level] = 1;
$current = &$current[$tag];
} else { //There was another element with the same tag name
if(isset($current[$tag][0])) {//If there is a 0th element it is already an array
$current[$tag][$repeated_tag_index[$tag.'_'.$level]] = $result;
$repeated_tag_index[$tag.'_'.$level]++;
} else {//This section will make the value an array if multiple tags with the same name appear together
$current[$tag] = array($current[$tag],$result);//This will combine the existing item and the new item together to make an array
$repeated_tag_index[$tag.'_'.$level] = 2;
if(isset($current[$tag.'_attr'])) { //The attribute of the last(0th) tag must be moved as well
$current[$tag]['0_attr'] = $current[$tag.'_attr'];
unset($current[$tag.'_attr']);
}
}
$last_item_index = $repeated_tag_index[$tag.'_'.$level]-1;
$current = &$current[$tag][$last_item_index];
}
} elseif($type == "complete") { //Tags that ends in 1 line '<tag />'
//See if the key is already taken.
if(!isset($current[$tag])) { //New Key
$current[$tag] = $result;
$repeated_tag_index[$tag.'_'.$level] = 1;
if($priority == 'tag' and $attributes_data) $current[$tag. '_attr'] = $attributes_data;
} else { //If taken, put all things inside a list(array)
if(isset($current[$tag][0]) and is_array($current[$tag])) {//If it is already an array...
// ...push the new element into that array.
$current[$tag][$repeated_tag_index[$tag.'_'.$level]] = $result;
if($priority == 'tag' and $get_attributes and $attributes_data) {
$current[$tag][$repeated_tag_index[$tag.'_'.$level] . '_attr'] = $attributes_data;
}
$repeated_tag_index[$tag.'_'.$level]++;
} else { //If it is not an array...
$current[$tag] = array($current[$tag],$result); //...Make it an array using using the existing value and the new value
$repeated_tag_index[$tag.'_'.$level] = 1;
if($priority == 'tag' and $get_attributes) {
if(isset($current[$tag.'_attr'])) { //The attribute of the last(0th) tag must be moved as well
$current[$tag]['0_attr'] = $current[$tag.'_attr'];
unset($current[$tag.'_attr']);
}
if($attributes_data) {
$current[$tag][$repeated_tag_index[$tag.'_'.$level] . '_attr'] = $attributes_data;
}
}
$repeated_tag_index[$tag.'_'.$level]++; //0 and 1 index is already taken
}
}
} elseif($type == 'close') { //End of tag '</tag>'
$current = &$parent[$level-1];
}
}
return($xml_array);
}
$xml = xml2array('[xml 内容]');
现在轻松使用 foreach :)
<?
$dom = simplexml_load_file("lectures.xml");
$items = 0;
foreach ($dom->item as $item) {
//what u want to do here
$items += 1;
}
?>
我认为您不需要 xpath，最好在您想在大 xml 文件中查找特定元素时使用它。
xpath query: /child::items/child::item