试试这个，使用preg_replace

$string = "Hello! 123 test this? 456. done? 100%";
$int = intval(preg_replace('/[^0-9]+/', '', $string), 10);
echo $int;

DEMO

使用preg_replace:

$str = '(111) 111-1111';
$str = preg_replace('/\D/', '', $str);
echo $str;

输出:1111111111

$str = 'In My Cart : 11 12 items';
preg_match_all('!\d+!', $str, $matches);
print_r($matches);

$value = '25%';

Or

$value = '25.025$';

Or

$value = 'I am numeric 25';
$onlyNumeric = filter_var($value, FILTER_SANITIZE_NUMBER_FLOAT, FILTER_FLAG_ALLOW_FRACTION);

这将只返回数值

试试这个，使用preg_replace

$string = "Hello! 123 test this? 456. done? 100%";
$int = intval(preg_replace('/[^0-9]+/', '', $string), 10);
echo $int;

DEMO

对于utf8 str:

function unicodeStrDigits($str) {
    $arr = array();
    $sub = '';
    for ($i = 0; $i < strlen($str); $i++) { 
        if (is_numeric($str[$i])) {
            $sub .= $str[$i];
            continue;
        } else {
            if ($sub) {
                array_push($arr, $sub);
                $sub = '';
            }
        }
    }

    if ($sub) {
        array_push($arr, $sub); 
    }

    return $arr;
}