preg_math multiply responce

<?php
$string = "Movies and Stars I., 32. part";
$pattern = "((IX|IV|V?I{0,3}[\.]))";

if(pr开发者_开发问答eg_match($pattern, $string, $x) == false)
{
    print "NAPAKA!";
}
else
{
    print_r($x);
}
?>

And the response is:

Array ( [0] => I. [1] => I. )

I should get only 1 response... Why do I get multiple responses?

---

The element at index 0 is the whole matched string. The element at index 1 is the contents of the first capture group, i.e. the content inside the parenthesis. In this case, they just happen to be the same. Just use $x[0] to get the value you're looking for.

---

The nested parenthesis should, in this instance, be a "non-capturing" subpattern.

$pattern = "~((?:IX|IV|V?I{0,3}[\.]))~";

Try that. It will tell the regex compiler to not capture the results of those parenthesis into the array.

In fact, looking at your regex, you don't even need those parenthesis. Make your regex this:

$pattern = "~IX|IV|V?I{0,3}[\.]~";

That should also work.

---

Your pattern has multiple groups in it -> the () brackets tell you what to capture in your match.

Try this:

$pattern = "(IX|IV|V?I{0,3}[\.])";

If you have a hard time identifying the wanted groups in the result you can name them as specified in the php.net documentation.

That would look something like this:

$pattern = "(?P<groupname>IX|IV|V?I{0,3}[\.])";

---

You get 0-indexed for all mathced string and result for every paretness (). it's helpful to get groups i.e

preg_match('~([0-9]+)([a-z]+)','12abc',$x);
$x is ([0]=>12abc [1]=>12 [2]=>abc)

In your case you can simply delete () (1 pair ot them, 1 pair is used as delimiters)