获取类方法的参数数量

Question

I know:

function params($fn) {
    $R = new ReflectionFunction($fn);
    return $R->getNumberOfParameters();
}

returns the number of parameters the function can accept, but how do I do this for a method that exists in a class?

Answer 1

You can for instance add a new parameter $clazz to your function, in order to give a scope to the method you want to know the number of arguments. Instead of using ReflectionFunction, use ReflectionClass in addition with ReflectionMethod.

function params($clazz, $method) { 
    $C = new ReflectionClass($clazz);
    $M = $C->getMethod($method);
    return $M->getNumberOfParameters();
}