function array2xml(array $data, SimpleXMLElement $object = null, $oldNodeName = 'item')
{
    if (is_null($object)) $object = new SimpleXMLElement('<root/>');
    $isNumbered = true;
    $idx = 0;
    foreach ($data as $key => $x)
        if (is_string($key) || ($idx++ != $key + 0))
            $isNumbered = false;
    foreach ($data as $key => $value)
    {   
        $attribute = preg_match('/^[0-9]/', $key . '') ? $key : null;
        $key = (is_string($key) && !preg_match('/^[0-9]/', $key . '')) ? $key : preg_replace('/s$/', '', $oldNodeName);
        if (is_array($value))
        {
            $new_object = $object->addChild($key);
            if (!$isNumbered && !is_null($attribute)) $new_object->addAttribute('id', $attribute);
            array2xml($value, $new_object, $key);
        }
        else
        {
            if (is_bool($value)) $value = $value ? 'true' : 'false';
            $node = $object->addChild($key, htmlspecialchars($value));
            if (!$isNumbered && !is_null($attribute) && !isset($node->attributes()->id))
                $node->addAttribute('id', $attribute);
        }
    }
    return $object;
}

例如，该函数返回一个<obj>…</obj><obj>…</obj>数值索引的XML标记。

输入:

    array(
    'people' => array(
        'dog',
        'cat',
        'life' => array(
            'gum',
            'shoe',
        ),
        'fish',
    ),
    array('yeah'),
)

输出:

<root>
    <people>
        <people>dog</people>
        <people>cat</people>
        <life>
            <life>gum</life>
            <life>shoe</life>
        </life>
        <people>fish</people>
        <people>
            <people>yeah</people>
        </people>
    </people>
</root>

这应该能满足所有的共同需求。也许你可以把第三行改成:

$key = is_string($key) ? $key : $oldNodeName . '_' . $key;

或者如果你正在处理以s结尾的复数:

$key = is_string($key) ? $key : preg_replace('/s$/', '', $oldNodeName);

这是我的入口，简单而干净。

function array2xml($array, $xml = false){
    if($xml === false){
        $xml = new SimpleXMLElement('<root/>');
    }
    foreach($array as $key => $value){
        if(is_array($value)){
            array2xml($value, $xml->addChild($key));
        }else{
            $xml->addChild($key, $value);
        }
    }
    return $xml->asXML();
}


header('Content-type: text/xml');
print array2xml($array);

下面是php 5.2代码，将数组的任何深度转换为xml文档:

Array
(
    ['total_stud']=> 500
    [0] => Array
        (
            [student] => Array
                (
                    [id] => 1
                    [name] => abc
                    [address] => Array
                        (
                            [city]=>Pune
                            [zip]=>411006
                        )                       
                )
        )
    [1] => Array
        (
            [student] => Array
                (
                    [id] => 2
                    [name] => xyz
                    [address] => Array
                        (
                            [city]=>Mumbai
                            [zip]=>400906
                        )   
                )

        )
)

生成的XML如下所示:

<?xml version="1.0"?>
<student_info>
    <total_stud>500</total_stud>
    <student>
        <id>1</id>
        <name>abc</name>
        <address>
            <city>Pune</city>
            <zip>411006</zip>
        </address>
    </student>
    <student>
        <id>1</id>
        <name>abc</name>
        <address>
            <city>Mumbai</city>
            <zip>400906</zip>
        </address>
    </student>
</student_info>

PHP代码片段

<?php
// function defination to convert array to xml
function array_to_xml( $data, &$xml_data ) {
    foreach( $data as $key => $value ) {
        if( is_array($value) ) {
            if( is_numeric($key) ){
                $key = 'item'.$key; //dealing with <0/>..<n/> issues
            }
            $subnode = $xml_data->addChild($key);
            array_to_xml($value, $subnode);
        } else {
            $xml_data->addChild("$key",htmlspecialchars("$value"));
        }
     }
}

// initializing or creating array
$data = array('total_stud' => 500);

// creating object of SimpleXMLElement
$xml_data = new SimpleXMLElement('<?xml version="1.0"?><data></data>');

// function call to convert array to xml
array_to_xml($data,$xml_data);

//saving generated xml file; 
$result = $xml_data->asXML('/file/path/name.xml');

?>

本代码段中使用的SimpleXMLElement::asXML文档

以上答案大部分是正确的。然而，我想出了这个答案，它解决了array_walk_recursive的兼容性问题，也解决了数值键的问题。它也通过了我做的所有测试:

function arrayToXML(Array $array, SimpleXMLElement &$xml) {

    foreach($array as $key => $value) {

        // None array
        if (!is_array($value)) {
            (is_numeric($key)) ? $xml->addChild("item$key", $value) : $xml->addChild($key, $value);
            continue;
        }   

        // Array
        $xmlChild = (is_numeric($key)) ? $xml->addChild("item$key") : $xml->addChild($key);
        arrayToXML($value, $xmlChild);
    }
}   

我还为此添加了一个测试类，你可能会发现有用:

class ArrayToXmlTest extends PHPUnit_Framework_TestCase {

    public function setUp(){ }
    public function tearDown(){ }

    public function testFuncExists() {
        $this->assertTrue(function_exists('arrayToXML'));
    }

    public function testFuncReturnsXml() {
        $array = array(
            'name' => 'ardi',
            'last_name' => 'eshghi',
            'age' => 31,
            'tel' => '0785323435'
        );

        $xmlEl =  new SimpleXMLElement('<root/>');
        arrayToXml($array, $xmlEl);

        $this->assertTrue($xmlEl instanceOf SimpleXMLElement);
    }

    public function testAssocArrayToXml() {

        $array = array(
            'name' => 'ardi',
            'last_name' => 'eshghi',
            'age' => 31,
            'tel' => '0785323435'
        );

        $expectedXmlEl = new SimpleXMLElement('<root/>'); 
        $expectedXmlEl->addChild('name', $array['name']);
        $expectedXmlEl->addChild('last_name', $array['last_name']);
        $expectedXmlEl->addChild('age', $array['age']);
        $expectedXmlEl->addChild('tel', $array['tel']);

        $actualXmlEl =  new SimpleXMLElement('<root/>');
        arrayToXml($array, $actualXmlEl);

        $this->assertEquals($expectedXmlEl->asXML(), $actualXmlEl->asXML());
    }

    public function testNoneAssocArrayToXml() {

        $array = array(
            'ardi',
            'eshghi',
            31,
            '0785323435'
        );

        // Expected xml value
        $expectedXmlEl = new SimpleXMLElement('<root/>'); 
        foreach($array as $key => $value)
            $expectedXmlEl->addChild("item$key", $value);

        // What the function produces       
        $actualXmlEl =  new SimpleXMLElement('<root/>');
        arrayToXml($array, $actualXmlEl);

        $this->assertEquals($expectedXmlEl->asXML(), $actualXmlEl->asXML());
    }

    public function testNestedMixArrayToXml() {

        $testArray = array(
            "goal",
            "nice",
            "funny" => array(
                'name' => 'ardi',
                'tel'   =>'07415517499',
                "vary",
                "fields" => array(
                    'small',
                    'email' => 'ardi.eshghi@gmail.com'
                ),

                'good old days'

            ),

            "notes" => "come on lads lets enjoy this",
            "cast" => array(
                'Tom Cruise',
                'Thomas Muller' => array('age' => 24)
            )
        );

        // Expected xml value
        $expectedXmlEl = new SimpleXMLElement('<root/>'); 
        $expectedXmlEl->addChild('item0', $testArray[0]);
        $expectedXmlEl->addChild('item1', $testArray[1]);
        $childEl = $expectedXmlEl->addChild('funny');
        $childEl->addChild("name", $testArray['funny']['name']);
        $childEl->addChild("tel", $testArray['funny']['tel']);
        $childEl->addChild("item0", "vary");
        $childChildEl = $childEl->addChild("fields");
        $childChildEl->addChild('item0', 'small');
        $childChildEl->addChild('email', $testArray['funny']['fields']['email']);
        $childEl->addChild("item1", 'good old days');
        $expectedXmlEl->addChild('notes', $testArray['notes']);
        $childEl2 = $expectedXmlEl->addChild('cast');
        $childEl2->addChild('item0', 'Tom Cruise');
        $childChildEl2 = $childEl2->addChild('Thomas Muller');
        $childChildEl2->addChild('age', $testArray['cast']['Thomas Muller']['age']);

        // What the function produces       
        $actualXmlEl = new SimpleXMLElement('<root/>');
        arrayToXml($testArray, $actualXmlEl);

        $this->assertEquals($expectedXmlEl->asXML(), $actualXmlEl->asXML());
    }
}      

另一个改进:

/**
* Converts an array to XML
*
* @param array $array
* @param SimpleXMLElement $xml
* @param string $child_name
*
* @return SimpleXMLElement $xml
*/
public function arrayToXML($array, SimpleXMLElement $xml, $child_name)
{
    foreach ($array as $k => $v) {
        if(is_array($v)) {
            (is_int($k)) ? $this->arrayToXML($v, $xml->addChild($child_name), $v) : $this->arrayToXML($v, $xml->addChild(strtolower($k)), $child_name);
        } else {
            (is_int($k)) ? $xml->addChild($child_name, $v) : $xml->addChild(strtolower($k), $v);
        }
    }

    return $xml->asXML();
}

用法:

$this->arrayToXML($array, new SimpleXMLElement('<root/>'), 'child_name_to_replace_numeric_integers');

function toXML($data, $obj = false, $dom) {
    $is_first_level = false;
    if($obj === false) {
        $dom = new DomDocument('1.0');
        $obj = $dom;
        $is_first_level = true;
    }

    if(is_array($data)) {
        foreach($data as $key => $item) {
            $this->toXML($item, $obj->appendChild($dom->createElement($key)), $dom);
        }
    }else {
        $obj->appendChild($dom->createTextNode($data));
    }

    if($is_first_level) {
        $obj->formatOutput = true;
        return $obj->saveXML();
    }
    return $obj;
}