Parse HTML in PHP and extract value [duplicate] - php

Question

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Why it's not possible to use regex to parse HTML/XML: a formal explanation in layman's terms
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What to do Regular expression pattern doesn't match anywhere in string?
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Closed 6 years ago.
I'm trying to extract some information from a website.
There is a section looking like that:
<th>Some text here</th><td>text to extract</td>
I would like to find (with regexp or other solution) the part starting with some text here and extract the text to extract from that.
I was trying to use following regexp solution:
$reg = '/<th>Some text here<\/th><td>(.*)<\/td>/';
preg_match_all($reg, $content, $result, PREG_PATTERN_ORDER);
print_r($result);
but it gives me just empty array:
Array ( [0] => Array ( ) [1] => Array ( ) )
How should I construct my regular expression to extract wanted value? Or what other solution can I use to extract it?

Answer 1

Using XPath:
$dom = new DOMDocument;
libxml_use_internal_errors(true);
$dom->loadHTML($html);
libxml_clear_errors();
$xp = new DOMXPath($dom);
$content = $xp->evaluate('string(//th[.="Some text here"]/following-sibling::*[1][name()="td"])');
echo $content;
XPath query details:
string( # return a string instead of a node list
// # anywhere in the DOM tree
th # a th node
[.="Some text here"] # predicate: its content is "Some text here"
/following-sibling::*[1] # first following sibling
[name()="td"] # predicate: must be a td node
)
The reason your pattern doesn't work is probably because the td content contains newlines characters (that are not matched by the dot .).

Answer 2

you could use a DOMDocument for this.
$domd=#DOMDocument::loadHTML($content);
$extractedText=NULL;
foreach($domd->getElementsByTagName("th") as $ele){
if($ele->textContent!=='Some text here'){continue;}
$extractedText=$ele->nextSibling->textContent;
break;
}
if($extractedText===NULL){
//extraction failed
} else {
//extracted text is in $extractedText
}
(regex is generally a bad tool for parsing HTML, as someone in comments have already pointed out)