How to get number from between brackets in string in PHP

How to get number from between brackets in string in PHP

Currently I use arrays such as this one for version control of a Mysql
database:
$pages_table = array (
"GUID" => array (
"type" => "CHAR(13)"
"length" => 13
)
"Number" => array (
"type" => "TINYINT(4)"
"length" => 4
)
"Pagename" => array (
"type" => "VARCHAR(30)"
"length" => 30
)
It works, but I want to make it more clean, like:
$pages_table = array (
"GUID" => "CHAR(13)"
"Number" => "TINYINT(4)"
"Pagename" => "VARCHAR(30)"
);
And then if I iterate over the array, I want to set $new_length (INT) to
the number between the brackets of the $new_type string:
while ($column = key($pages_table)) {
$new_type = current($pages_table);
$new_length = //Get this value from $new_type;
if ($existing_table[$column]['length'] < $new_length) {
$modify[$column] => $new_type;
}
next($pages_table);
}