ansaurus

Question

getting all values from h1 tags using php

Answer 1

+14 A:

function getTextBetweenTags($string, $tagname) {
    // Create DOM from string
    $html = str_get_html($string);

    $titles = array();
    // Find all tags 
    foreach($html->find($tagname) as $element) {
        $titles[] = $element->plaintext;
    }
}

kgb 2010-07-21 12:18:07

Oooh I didn't know you could do that!

Rimian 2010-07-21 12:26:07

+1 for DomParser, handy tool

DavidYell 2010-07-21 12:38:24

Is simplehtmldom any faster then DOMDocument or just for those occasions where DOMDocument doesn't exist (although it's enabled by default)?

Wrikken 2010-07-21 12:39:16

Thank you for your fast reply and excellent solution! :)

Pieter888 2010-07-21 12:40:43

@Wrikken it is userland code, so it doubt it is faster. Dunno why people are so fascinated with it (must be the *simple* in the name), especially because there is also [Zend_Dom](http://framework.zend.com/manual/en/zend.dom.query.html), [phpquery](http://code.google.com/p/phpquery/) or [FluentDom](http://nightly.fluentdom.org/documentation) for alternatives.

Gordon 2010-07-21 12:49:36

@Wrikken it isn't faster(almost the same), but handles invalid html better. also much less problems with non-utf encodings...

kgb 2010-07-21 12:49:58

@kgb you [claimed this before](http://stackoverflow.com/questions/3220076/php-domdocument-how-can-i-print-an-attribute-of-an-element/3220084#3220084) but I still refute it. DOM handles HTML fine.

Gordon 2010-07-21 12:52:39

i've had a better example, but now i could find only this: http://stackoverflow.com/questions/1183482/cant-separate-cells-properly-with-simplehtmldom. the point is - simplehtmldom works if the html is not a valid tree.. and i don't like putting "@" to suppress warnings ;)

kgb 2010-07-21 13:01:57

@kgb DOM can load invalid HTML fine if you load it with loadHTML. The only thing not working then is getElementById and that is solely due to the fallback to the HTML4.0 DTD. You can still very much query nodes by ID via XPath then. Also, you do not have to suppress the errors with @ at all. You can use libxml_use_internal_errors and handle any errors by custom error handlers. SimpleHTMLDom isnt more suitable for HTML. It doesnt even use libxml but parses the HTML with String functions.

Gordon 2010-07-21 13:22:50

point taken, thanks for clarification..

kgb 2010-07-21 13:28:20

I'd take 'can report errors but is configurable to keep quiet' above 'will not tell you when something is up' any time of the week :)

Wrikken 2010-07-21 15:52:33

-1 for not using the built in c extension to do the exact same thing (Seriously, why do things in PHP if the exact same thing is built into the PHP core?)... Use `DomDocument` instead...

ircmaxell 2010-07-21 15:56:34

Answer 2

+6 A:

function getTextBetweenTags($string, $tagname){
    $d = new DOMDocument();
    $d->loadHTML($string);
    $return = array();
    foreach($d->getElementsByTagName($tagname) as $item){
        $return[] = $item->textContent;
    }
    return $return;
}

Wrikken 2010-07-21 12:20:19

oh. beat me to it. didnt see.

Gordon 2010-07-21 12:27:33

Answer 3

+1 A:

 function getTextBetweenH1($string)
 {
    $pattern = "/<h1>(.*?)<\/h1>/";
    preg_match_all($pattern, $string, $matches);
    return ($matches[1]);
 }

dejavu 2010-07-21 12:24:29

Please do not parse HTML with regular expressions! http://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags/1732454#1732454

Török Gábor 2010-07-21 12:31:29

Using regex is quite fine here. He isn't parsing HTML. He is matching stuff between `<h1>` and `</h1>`, which is inherently regular. Matching a regular language with regular expressions is quite fine. Drop the mindless "OMG regex cannot be used for anything if there is HTML involved" crap that everybody seems to be hyping. It's not like he is trying to match all of HTML, only a very small subset of the language which happens to be regular.

Daniel Egeberg 2010-07-21 13:17:52

@Daniel what if there is attributes to the `<h1>`? What if the headings contain element children?

Gordon 2010-07-21 13:28:51

@Gordon: The attribute problem can be solved using this regex: `#<h1(?:"(?:[^\\\"]|\\\.)*"|\'(?:[^\\\\\']|\\\.)*\'|[^\'">])*>(.*?)</h1>#i` (which I believe still describes a regular language and thus can be represented using a finite state machine). The problem with child elements is non-existent because there cannot be an `<h1>` within another `<h1>` anyways. Edit: The regex is written for a single-quoted PHP string.

Daniel Egeberg 2010-07-21 13:51:58

@Daniel you have to admit that this is completely unreadable :) Also, there can be inline elements in an h1. What about spans? strongs? ems? The h1 of this very page has a link inside. Regex has no concept of TextNodes. It just knows Strings.

Gordon 2010-07-21 13:56:31

Answer 4

+2 A:

Alternative to DOM. Use when memory is an issue.

$html = <<< HTML
<html>
<h1>hello<span>world</span></h1>
<p>random text</p>
<h1>title number two!</h1>
</html>
HTML;

$reader = new XMLReader;
$reader->xml($html);
while($reader->read() !== FALSE) {
    if($reader->name === 'h1' && $reader->nodeType === XMLReader::ELEMENT) {
        echo $reader->readString();
    }
}

Gordon 2010-07-21 12:26:12

thanks, I'm still using the DOM method though. Still thank you for taking your time answering :)

Pieter888 2010-07-21 12:43:54

@Pieter yup, I had supplied the DOM solution myself if Wrikken hadnt already done so.

Gordon 2010-07-21 12:46:18

ansaurus

tags:

views:

answers:

getting all values from h1 tags using php

related questions