How to get a particular data from from the scraped webpage in php

Question

Possible Duplicate:
How to parse and process HTML with PHP?

Hi there I have scraped a web page

  <div class="col blue">
        <img  src="/en/media/Dentalscreenresized.jpg" />
        <h4>This is line i want to scrape</h4>
        <p class="date">12 Sep
            <span class="year">2012</span></p>
        <p>13 people were diagnosed with oral cancer after last year&rsquo;s Mouth Cancer Awareness Day. Ring 021-4901169 to arrange for a free screening on the 19th September.</p>
        <p class="readmore"><a href="/en/news/abcd.html">Read More</a></p>
        <p class="rightreadmore"><a href="http://www.xyz.ie/en/news/">See all News&nbsp;&nbsp;&nbsp;</a></p>
    </div>

Now i want to display the <h4> tag of class="col blue".I seen online to use preg_match_all() I am not familiar with regular expression... any help please

score 1 · Answer 1 · edited Jun 10 '21 at 12:00

Don't use Regular Expressions to parse HTML. It may seem difficult to use libraries and dedicated solutions. You can find a lot of "Don't use regex" answers out there.

I'd recommend SimpleHTMLDOM which is simple to use.

    <?php
// include necessary classes first.
// e.g. include('simple_html_dom.php'); // assuming the file is in same folder as the php file. Or include it at first or you will get a fatal error.
    $html = str_get_html('<div class="col blue">
            <img  src="/en/media/Dentalscreenresized.jpg" />
            <h4>This is line i want to scrape</h4>
            <p class="date">12 Sep
                <span class="year">2012</span></p>
            <p>13 people were diagnosed with oral cancer after last year&rsquo;s Mouth Cancer Awareness Day. Ring 021-4901169 to arrange for a free screening on the 19th September.</p>
            <p class="readmore"><a href="/en/news/abcd.html">Read More</a></p>
            <p class="rightreadmore"><a href="http://www.xyz.ie/en/news/">See all News&nbsp;&nbsp;&nbsp;</a></p>
        </div>
    ');
    
    $h4 = $html->find('h4.col.blue');
    ?>

Now $h4 contains all elements with the h4 tag with col and blue classes.

the above code given me the below error:) Fatal error: Call to undefined function str_get_html() — user1529342, Sep 13 '12 at 09:57
see new code please. you need to include the library i mentioned or you will see this error. — AKS, Sep 13 '12 at 10:01

raina77ow · Accepted Answer · 2012-09-13T10:46:14.180

Well, as often in life, you have two options here (I assume that scraped page's content is stored in $content variable):

The Way of ~~(Cthulhu)~~ Regex:

$matches = array();
preg_match_all('#<div class="col blue">.+?<h4>([^<]+)#is', $content, $matches);
var_dump($matches[1]);

The Way of DOM Parsing:

$dom = new DOMDocument();
$dom->loadHTML($content);
$xpath = new DOMXpath($dom);
$elements = $xpath->query('//div[@class="col blue"]/h4');
foreach ($elements as $el) {
   var_dump($el->textContent);
}

And the real question, of course, is what way to choose.

The first option is short, concise, and quite seductive overall. I admit I would use it once, twice, or (pony he comes) even more - IF and only IF I know that HTML I work with will always come to me normalized AND I can cope with its structure suddenly changing in a non-predictable way.

The second option is slightly bigger, and may look too generic. Yet it's way more flexible and resilient to changes in the source, in my opinion.

For example, consider what happens if some 'blue-colored' divs in the source HTML may come out without <h4> element. To work correctly in such conditions, the regex will have to become much more sophisticated. And the XPath query? Won't change - even a slightest bit.

its really a precious explanation.... Thanks for the help.... — user1529342, Sep 13 '12 at 11:09

score 0 · Answer 3 · answered Sep 13 '12 at 09:53

0

Don't use regular expressions to parse/scrape info from HTML, try a DOM parser like the one built into PHP.

answered Sep 13 '12 at 09:53

newenglander

2,019
24
55

can you explain bit more clearly – user1529342 Sep 13 '12 at 09:54
As Ayesh K mentions, there are a lot of "Don't use regex" answers out, try doing a search here or on google. – newenglander Sep 13 '12 at 09:56

score 0 · Answer 4 · answered Sep 13 '12 at 10:11

Use DOM and Xpath. put your html data in $html.

$dom = new DOMDocument('1.0', 'UTF-8');
@$dom->loadHTML($html);
$xmlElements = simplexml_import_dom($dom);

$divs = $xmlElements->xpath("//div[@class='col blue']");
foreach($divs as $div)
{
  $heading = $div->h4;
  var_dump($heading);
}

Additional Note:

Don't use regular expressions to parse/scrape info from HTML. Its a Bad technique

How to get a particular data from from the scraped webpage in php

4 Answers4