Retrieving partial content from string in PHP

I'm trying to figure out a function that recognizes content within brackets and is able to return that content. Like so:

$str = "somedynamiccontent[1, 2, 3]"
echo function($str); // Will output "1,开发者_运维知识库 2, 3"

Anybody here who can help? Thanks for your time.

preg_match("/\[(.+)\]/",$string,$matches);
echo $matches[1];

Simple example with regex (this will match all occurances):

<?php
$subject = 'hello [1,2,3], testing 123 [hello], test [_"_£!"_£]';
preg_match_all('/\[([^\]]+)\]/', $subject, $matches);


foreach ($matches[1] as $match) {

    echo $match . '<br />';
}

or just the one:

<?php
$subject = 'hello [1,2,3], testing 123 [hello], test [_"_£!"_£]';
preg_match('/\[([^\]]+)\]/', $subject, $match);


echo $match[1] . '<br />';

EDIT:

Combined into a simple function...

<?php
$subject = 'hello [1,2,3], testing 123 [hello], test [_"_£!"_£]';

function findBrackets($subject, $find_all = true) 
{
    if ($find_all) {
        preg_match_all('/\[([^\]]+)\]/', $subject, $matches);

        return array($matches[1]);
    } else {

        preg_match('/\[([^\]]+)\]/', $subject, $match);

        return array($match[1]);
    }
}

// Usage:
echo '<pre>';

$results =  findBrackets('this is some text [1, 2, 3, 4, 5] [3,4,5] [test]', false); // Will return an array with 1 result

print_r($results);

$results = findBrackets('this is some text [1, 2, 3, 4, 5] [3,4,5] [test]'); // Will return an array with all results

print_r($results);

echo '</pre>';