Xpath Regex in PHP not working

问题

Here is my XML that is returned:

<?xml version="1.0" encoding="utf-8"?>
    <lists>
        <list>
            <id>6791</id>
            <title><![CDATA[List 1]]></title>
            <type>0</type>
            <priority>0</priority>
            <due><![CDATA[0000-00-00 00:00:00]]></due>
            <notes><![CDATA[]]></notes>
            <user_id>49211</user_id>
            <owner><![CDATA[]]></owner>
            <item1>
                <done>0</done>
                <title><![CDATA[Bamboo Montage-83 Knee High Studded Contrast Colored Zipper Riding Boot - Brown PU]]></title>
                <barcode>B00H2Y2UY6</barcode>
                <priority>2</priority>
                <item_id>57741</item_id>
            </item1>
            <item2>
                <done>0</done>
                <title><![CDATA[List 2]]></title>
                <barcode><![CDATA[]]></barcode>
                <priority>2</priority>
                <item_id>57751</item_id>
            </item2>
            <item3>
                <done>0</done>
                <title><![CDATA[List Item 1]]></title>
                <barcode><![CDATA[]]></barcode>
                <priority>2</priority>
                <item_id>57761</item_id>
            </item3>
        </list>

i wanted to get the list->item[0-9] node which is appended with a number i am using PHP's SimpleXMLElementclass to get them but i am unable to get the node with regular expression here is my code:

    foreach ($list_xml->lists->xpath("/list/^item[0-9]$") as $listItem) {
             echo $listItem->title;
    }

note a dump of $list_xml is like this:

SimpleXMLElement Object
(

[lists] => SimpleXMLElement Object
    (
        [list] => Array
            (
                [0] => SimpleXMLElement Object
                    (
                        [id] => 6791
                        [title] => SimpleXMLElement Object
                            (
                            )

                        [type] => 0
                        [priority] => 0
                        [due] => SimpleXMLElement Object
                            (
                            )

                        [notes] => SimpleXMLElement Object
                            (
                            )

                        [user_id] => 49211
                        [owner] => SimpleXMLElement Object
                            (
                            )

                        [item1] => SimpleXMLElement Object
                            (
                                [done] => 0
                                [title] => SimpleXMLElement Object
                                    (
                                    )

                                [barcode] => B00H2Y2UY6
                                [priority] => 2
                                [item_id] => 57741
                            )

                        [item2] => SimpleXMLElement Object
                            (
                                [done] => 0
                                [title] => SimpleXMLElement Object
                                    (
                                    )

                                [barcode] => SimpleXMLElement Object
                                    (
                                    )

                                [priority] => 2
                                [item_id] => 57751
                            )

                        [item3] => SimpleXMLElement Object
                            (
                                [done] => 0
                                [title] => SimpleXMLElement Object
                                    (
                                    )

                                [barcode] => SimpleXMLElement Object
                                    (
                                    )

                                [priority] => 2
                                [item_id] => 57761
                            )

                    )
           )
    )

回答1:

SimpleXmlElement is backed by libxml2 which supports XPath 1.0 only. XPath 1.0 doesn't support string matching with regular expressions, XPath 2.0 does.

So two options are open:

Option 1: Stay with XPath 1.0

In this case, you can try to build on the fly the xpath query for matching all the item* nodes:

$items=array();
for($i=0; $i<10; $i++) {
   $items[] = '/list/item' . $i;
}
$xpath=join($items, '|'); // $xpath == '/list/item1|/list/item2| ...'

Option 2: Move to XPath 2.0

There is no plan for adding this support to PHP. Read this SO question: (What is the best way to use XSLT 2.0 with PHP?) for finding a workaround. As of this writing, it is one of the most actual about this subject.

来源：https://stackoverflow.com/questions/21138875/xpath-regex-in-php-not-working

标签

php

regex

xpath

simplexml