PHP. Руководство по PHP. 2005

xml_parse_into_structПред.

xml_parse_into_struct

(PHP 3 >= 3.0.8, PHP4, PHP 5)xml_parse_into_struct -- Parse XML data into an array structure

Description

int xml_parse_into_struct (resource parser, string data, array &values [, array &index])

This function parses an XML file into 2 parallel array structures, one (index) containing pointers to the location of the appropriate values in the values array. These last two parameters must be passed by reference.

Замечание: xml_parse_into_struct() returns 0 for failure and 1 for success. This is not the same as FALSE and TRUE, be careful with operators such as ===.

Below is an example that illustrates the internal structure of the arrays being generated by the function. We use a simple note tag embedded inside a para tag, and then we parse this and print out the structures generated:

Пример 1. xml_parse_into_struct() example


<?
$simple = "<para><note>simple note</note></para>";
$p = xml_parser_create();
xml_parse_into_struct($p, $simple, $vals, $index);
xml_parser_free($p);
echo "Index array\n";
print_r($index);
echo "\nVals array\n";
print_r($vals);

?>

When we run that code, the output will be:

Index array
Array
([PARA] => Array ([0] => 0 [1] => 2
)
[NOTE] => Array ([0] => 1
))
Vals array
Array
([0] => Array ([tag] => PARA [type] => open [level] => 1
)
[1] => Array ([tag] => NOTE [type] => complete [level] => 2 [value] => simple note
)
[2] => Array ([tag] => PARA [type] => close [level] => 1
))

Event-driven parsing (based on the expat library) can get complicated when you have an XML document that is complex. This function does not produce a DOM style object, but it generates structures amenable of being transversed in a tree fashion. Thus, we can create objects representing the data in the XML file easily. Let's consider the following XML file representing a small database of aminoacids information:

Пример 2. moldb.xml - small database of molecular information

<?xml version="1.0"?>
<moldb>
<molecule> <name>Alanine</name> <symbol>ala</symbol> <code>A</code> <type>hydrophobic</type> </molecule>
<molecule> <name>Lysine</name> <symbol>lys</symbol> <code>K</code> <type>charged</type> </molecule>
</moldb>

And some code to parse the document and generate the appropriate objects:

Пример 3. parsemoldb.php - parses moldb.xml into an array of molecular objects


<?
class AminoAcid {
var $name; //aa name
var $symbol; //three letter symbol
var $code; //one letter code
var $type; //hydrophobic, charged or neutral
function AminoAcid ($aa)
{
foreach ($aa as $k=>$v)
$this->$k = $aa[$k];
}}
function readDatabase($filename)
{
//read the XML database of aminoacids
$data = implode("", file($filename));
$parser = xml_parser_create();
xml_parser_set_option($parser, XML_OPTION_CASE_FOLDING, 0);
xml_parser_set_option($parser, XML_OPTION_SKIP_WHITE, 1);
xml_parse_into_struct($parser, $data, $values, $tags);
xml_parser_free($parser);
//loop through the structures
foreach ($tags as $key=>$val){
if ($key == "molecule"){
$molranges = $val;
//each contiguous pair of array entries are the
//lower and upper range for each molecule definition
for ($i=0; $i < count($molranges); $i+=2){
$offset = $molranges[$i] + 1;
$len = $molranges[$i + 1] - $offset;
$tdb[] = parseMol(array_slice($values, $offset, $len));
}}else{
continue;
}}
return $tdb;
}
function parseMol($mvalues)
{
for ($i=0; $i < count($mvalues); $i++){
$mol[$mvalues[$i]["tag"]] = $mvalues[$i]["value"];
}
return new AminoAcid($mol);
}
$db = readDatabase("moldb.xml");
echo "** Database of AminoAcid objects:\n";
print_r($db);

?>

After executing parsemoldb.php, the variable $db contains an array of AminoAcid objects, and the output of the script confirms that:

** Database of AminoAcid objects:
Array
([0] => aminoacid Object ([name] => Alanine [symbol] => ala [code] => A [type] => hydrophobic
)
[1] => aminoacid Object ([name] => Lysine [symbol] => lys [code] => K [type] => charged
))

xml_get_error_code

xml_parse

Отвечу на любые вопросы. С уважением, Дмитрий Владимирович.

Ваше письмо	×