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POHow can this xpath query (PHP) be more flexible?
 

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  1. POHow can this xpath query (PHP) be more flexible?
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    <p>I'm parsing an XHTML document using PHP's SimpleXML. I need to query a series of ul's in the document for a node containing a specific value, then find that node's parent's direct previous sibling... code will help explain!</p> <p>Given the following dummy xhtml:</p> <pre><code>&lt;html&gt; &lt;head&gt;&lt;/head&gt; &lt;body&gt; ... &lt;ul class="attr-list"&gt; &lt;li&gt;Active Life (active)&lt;/li&gt; &lt;ul&gt; &lt;li&gt;Amateur Sports Teams (amateursportsteams)&lt;/li&gt; &lt;li&gt;Amusement Parks (amusementparks)&lt;/li&gt; &lt;li&gt;Fitness &amp; Instruction (fitness)&lt;/li&gt; &lt;ul&gt; &lt;li&gt;Dance Studios (dancestudio)&lt;/li&gt; &lt;li&gt;Gyms (gyms)&lt;/li&gt; &lt;li&gt;Martial Arts (martialarts)&lt;/li&gt; &lt;li&gt;Pilates (pilates)&lt;/li&gt; &lt;li&gt;Swimming Lessons/Schools (swimminglessons)&lt;/li&gt; &lt;/ul&gt; &lt;li&gt;Go Karts (gokarts)&lt;/li&gt; &lt;li&gt;Mini Golf (mini_golf)&lt;/li&gt; &lt;li&gt;Parks (parks)&lt;/li&gt; &lt;ul&gt; &lt;li&gt;Dog Parks (dog_parks)&lt;/li&gt; &lt;li&gt;Skate Parks (skate_parks)&lt;/li&gt; &lt;/ul&gt; &lt;li&gt;Playgrounds (playgrounds)&lt;/li&gt; &lt;li&gt;Rafting/Kayaking (rafting)&lt;/li&gt; &lt;li&gt;Tennis (tennis)&lt;/li&gt; &lt;li&gt;Zoos (zoos)&lt;/li&gt; &lt;/ul&gt; &lt;li&gt;Arts &amp; Entertainment (arts)&lt;/li&gt; &lt;ul&gt; &lt;li&gt;Arcades (arcades)&lt;/li&gt; &lt;li&gt;Art Galleries (galleries)&lt;/li&gt; &lt;li&gt;Wineries (wineries)&lt;/li&gt; &lt;/ul&gt; &lt;li&gt;Automotive (auto)&lt;/li&gt; &lt;ul&gt; &lt;li&gt;Auto Detailing (auto_detailing)&lt;/li&gt; &lt;li&gt;Auto Glass Services (autoglass)&lt;/li&gt; &lt;li&gt;Auto Parts &amp; Supplies (autopartssupplies)&lt;/li&gt; &lt;/ul&gt; &lt;li&gt;Nightlife (nightlife)&lt;/li&gt; &lt;ul&gt; &lt;li&gt;Bars (bars)&lt;/li&gt; &lt;ul&gt; &lt;li&gt;Dive Bars (divebars)&lt;/li&gt; &lt;/ul&gt; &lt;/ul&gt; &lt;/ul&gt; ... &lt;/body&gt; &lt;/html&gt; </code></pre> <p>I need to be able to query the ul.attr-list for a child element, and discover its "root" category. I cannot change the xhtml to be formed differently.</p> <p>So, if I have "galleries" as a category, I need to know that it is in the "arts" "root" category. Or, if I have "dog_parks", I need to know that it is in the "active" category. The following code gets the job done, but only with the assumption that at max there are two nested levels:</p> <pre><code>function get_root_category($shortCategoryName){ $url = "http://www.yelp.com/developers/documentation/category_list"; $result = file_get_contents($url); $dom = new domDocument(); @$dom-&gt;loadHTML($result); $dom-&gt;preserveWhiteSpace = false; $sxml = simplexml_import_dom($dom); $lvl1 = $sxml-&gt;xpath("//li[contains(., '".$shortCategoryName."')]/parent::ul/preceding-sibling::li"); $lvl2 = $sxml-&gt;xpath("//li[contains(., '".$shortCategoryName."')]/parent::ul/preceding-sibling::li/parent::ul/preceding-sibling::li"); if($lvl2){ return array_pop($lvl2); } else { return array_pop($lvl1); } } </code></pre> <p>There has to be a better way to write that XPath, so that only one query needs to be made, and is relatively bulletproof to multiple, nested levels.</p> <p>EDIT:: Thanks to those that pointed out that this HTML is not valid. However, the structure of the page is set, and I cannot edit it; I can only use it as a resource, and have to make due with what it is. </p>
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    1. UShakre
    1. USAndrew
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    1. COthis is invalid xhtml btw - nested ul should be direct child of li element.
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      1. USAdam Kiss
    2. COThanks, Adam, but I have no control over the actual HTML.
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      1. USAndrew
 

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