Get all method names starting with a substring from a PHP object

You can use preg_grep() to filter them:

$method_names = preg_grep('/^bla_/', get_class_methods($object));

Try:

$methods = array();
foreach (get_class_methods($myObj) as $method) {
    if (strpos($method, "bla_") === 0) {
        $methods[] = $method;
    }
}

Note that === is necessary here. == won't work, since strpos() returns false if no match was found. Due to PHPs dynamic typing this is equal to 0 and therefore a strict (type safe) equality check is needed.

Why don't you just make your own function that loops through the array from get_class_methods() and tests each element against "bla_" and returns a new list with each matching value?