php explode select multi choose

I want divide these html as serval several part. One <h2> or <h3> with some <p> and <span> as one part. I tried explode array('<h2>','<h3>'), but it caused Warning. the explode not support multi choose.

So how to do it perfectly? Thanks.

$text=<<<EOT
<h2>title1</h2>
<p>something</p>
<span>something</span>
<h3>title2</h3>
<p>something</p>
<p>something</p>
<p>something</p>
<h2>title3</h2>
<span&g开发者_开发百科t;something</span>
<h2>title4</h2>
<span>something</span>
<p>something</p>
<p>something</p>
EOT;

foreach ($text as $result) { 
    $arr = explode(array('<h2>','<h3>'),$result);
    reset($arr); 
    foreach($arr as $line){
        echo $line.'<hr />';
    } 
}

Warning: Invalid argument supplied for foreach() on line 23;

My expected output is:

<h2>title1</h2>
<p>something</p>
<span>something</span>
___________________________
<h3>title2</h3>
<p>something</p>
<p>something</p>
<p>something</p>
___________________________
<h2>title3</h2>
<span>something</span>
___________________________
<h2>title4</h2>
<span>something</span>
<p>something</p>
<p>something</p>
___________________________

You can use preg_split() to explode at different things. You can use RegEx here:

$text = <<<EOT
<h2>title1</h2>
<p>something</p>
...
EOT;

$arr = preg_split("#(?=<h[23]>)#", $text);

if(isset($arr[0]) && trim($arr[0])=='') array_shift($arr); // remove first block if empty

foreach($arr as $block){
    echo $block."<hr />\n";
}

You should use a parser for this kind of tasks. I use Zend Framework which has a parser component. Otherwise you can use plain PHP DOMElement. Then you can query your dom with xpath or css selectors. Example:

<?php

$text=<<<EOT
<h2>title1</h2>
<p>something</p>
<span>something</span>
<h3>title2</h3>
<p>something</p>
<p>something</p>
<p>something</p>
<h2>title3</h2>
<span>something</span>
<h2>title4</h2>
<span>something</span>
<p>something</p>
<p>something</p>
EOT;


require_once 'Zend/Dom/Query.php';

$dom = new Zend_Dom_Query($text);
$results = $dom->query('h2');

foreach ($results as $domEl) {
    var_dump($domEl->nodeValue);
}
// outputs:
// string(6) "title1"
// string(6) "title3"
// string(6) "title4"

Edit: Given your expected output, my example doesn't fit exactly your needs, but you still need a parser to do that kind of HTML manipulation, because the parser splits the HTML in elements and you can manipulate them as tokens, not as text.

Ok, first, the warning is addressed to the foreach, not the explode. You are trying to loop a string ($text in this case) instead of an array.

Second, even if $text would be of type array and $result would be of type string, you are trying to use an array as delimiter in the explode() call, but that function wants the 1st parameter to be of type string.

I'd recommend to have a look at How to parse HTML with PHP? or to search SO for this terms, to find many many posts dealing with how to parse HTML with PHP.