$mobile_array = explode(",",$mobile_list);        // turn into an array
$landlines = array_count_values($mobile_array);  // create count variable
echo $landlines["020..."];                      // print the number of numbers

$mobile_list = '02000, 02032435, 039002300, 00305600';
$mobile_array = explode(",",$mobile_list);        // turn into an array
$landlines = array_count_values($mobile_array);  // create count variable
$sequence = '020';                      // print the number of numbers



function filter_phone_numbers($mobile_array, $sequence){
    return array_filter($mobile_array, function ($item) use ($sequence) {
        if (stripos($item, $sequence)) {
            return true;
        }
        return false;
    });
}

$filtered_items = filter_phone_numbers($mobile_array, $sequence);

echo count($filtered_items);

$mobile_list = '02000, 02032435, 039002300, 00305600';
$mobile_array = explode(",",$mobile_list);        // turn into an array
$landlines = array_count_values($mobile_array);  // create count variable
$sequence = preg_quote('020', '~'); ;                      // print the number of numbers



function grep_phone_numbers($mobile_array, $sequence){

     return preg_grep('~' . $sequence . '~', $mobile_array);

}

$filtered_items = grep_phone_numbers($mobile_array, $sequence);

echo count($filtered_items);

$numbers = [
    '07000000000',
    '02000000000',
    '07000000000',
    '07000000000',
    '02000000000',
];
function landlineCount($carry, $item)
{
    if (substr($item, 0, 3) === '020') {
        return $carry += 1;
    }

    return $carry;
}


$count = array_reduce($numbers, 'landlineCount');

echo $count;

SELECT * FROM phone_numbers WHERE number LIKE '020%'

$mobile_list = "071234567890,02039989435,0781,020122,123020";

preg_match_all("/b020d+b/", $mobile_list, $m);
var_dump($m);
echo count($m[0]); // 2

$no = "020XXXXXXX";

if (strpos($no, '020') !== false) {
    echo 'its a landline number';
}