如何将XML转换为关联数组并控制将哪些属性用作名称值对？

$xmlString = '<root>
    <person>
        <name>John Doe</name>
        <age>30</age>
        <gender>Male</gender>
    </person>
    <person>
        <name>Jane Smith</name>
        <age>25</age>
        <gender>Female</gender>
    </person>
</root>';

$xml = simplexml_load_string($xmlString);
$json = json_encode($xml);
$array = json_decode($json, true);

print_r($array);

Array
(
    [person] => Array
        (
            [0] => Array
                (
                    [name] => John Doe
                    [age] => 30
                    [gender] => Male
                )

            [1] => Array
                (
                    [name] => Jane Smith
                    [age] => 25
                    [gender] => Female
                )

        )

)

$xmlString = '<root>
    <person>
        <name>John Doe</name>
        <age>30</age>
        <gender>Male</gender>
    </person>
    <person>
        <name>Jane Smith</name>
        <age>25</age>
        <gender>Female</gender>
    </person>
</root>';

$xml = simplexml_load_string($xmlString);

// 选择只包含name和age属性的person元素
$selectedXml = $xml->xpath('//person[not(gender)]');

$json = json_encode($selectedXml);
$array = json_decode($json, true);

print_r($array);

Array
(
    [0] => Array
        (
            [name] => John Doe
            [age] => 30
        )

    [1] => Array
        (
            [name] => Jane Smith
            [age] => 25
        )

)