In php, how can I use a regular expression to capture everything between two patterns (and the shortest instance of each pattern)?

Question

I must be overcomplicating this, but I can't figure it out for the life of me.

I have a standard html document stored as a string, and I need to get the contents of the paragraph. I'll make an example case.

$stringHTML=
"<html>

<head>
<title>Title</title>
</head>

<body>

<p>This is the first paragraph</p>
<p>This is the second</p>
<p>This is the third</p>
<p>And fourth</p>

</body>
</html>";

If I use

$regex='~(<p>)(.*)(</p>)~i';
preg_match_all($regex, $stringHTML, $newVariable);

I won't get 4 results. Rather, I'll get 10. I get 10 because the regex matches the first  and first  as well as the first  and fourth 

How can I search between two words, and return only the results of whats between each paragraph?

I know, and thanks for the tip but this is actually just for regex practice, so if it comes up in other situations, I'll be up to the job. — , Jan 01 '13 at 04:53
I suggest you find something more useful to practice on, then. — Andy Lester, Jan 01 '13 at 06:23

score 1 · Answer 1 · edited May 23 '17 at 10:24

Use HTML parser like DOM or XPATH to parse HTML. Dont use Regex to parse HTML. Here is how it can be easily parsed by DOMDocument.

$doc = new \DOMDocument;
$doc->loadHTML($stringHTML);
$ps = $doc->getElementsByTagName("p");
for($i=0;$i<$ps->length; $i++){
    echo $ps->item($i)->textContent. "\n";
}

Code in action

Using this RegEx (as you said its a regex practice) you'll get 4 results.

preg_match_all("#<p>(.*)</p>#", $stringHTML, $matches);
print_r($matches[1]);

Here look around syntaxes are used. See the code in action.

score 0 · Accepted Answer · answered Jan 01 '13 at 04:51

0

Use .*? to get the shortest match instead of the longest match.

answered Jan 01 '13 at 04:51

Barmar

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And this will yield 4 results? – Jan 01 '13 at 04:53
Why don't you "give it a go"! – happy coder Jan 01 '13 at 04:59
array(4) { [0]=> array(4) { [0]=> string(34) " This is the first paragraph " [1]=> string(25) " This is the second " [2]=> string(24) " This is the third " [3]=> string(17) " And fourth " } [1]=> array(4) { [0]=> string(3) " " [1]=> string(3) " " [2]=> string(3) " " [3]=> string(3) " " } [2]=> array(4) { [0]=> string(27) "This is the first paragraph" [1]=> string(18) "This is the second" [2]=> string(17) "This is the third" [3]=> string(10) "And fourth" } [3]=> array(4) { [0]=> string(4) " " [1]=> string(4) " " [2]=> string(4) " " [3]=> string(4) " " } } – Jan 01 '13 at 05:09
... Not what I wanted, but still easier to chop up. – Jan 01 '13 at 05:10
You seem to be printing it out as HTML, so you're not seeing the tags that were matched by `(
)` and `(
)`. – Barmar Jan 01 '13 at 05:20

score 0 · Answer 3 · answered Jan 01 '13 at 05:59

0

Your regex should be /(.*?)<\/p>/i . It will only matches the strings between  and put it in an array.

you shouldn't do a group : ()

answered Jan 01 '13 at 05:59

revo

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In php, how can I use a regular expression to capture everything between two patterns (and the shortest instance of each pattern)?

3 Answers3