$reflection = new ReflectionFunction('implode');
echo $reflection->getNumberOfParameters();
(PHP 5 >= 5.3.0, PHP 7, PHP 8)
ReflectionFunctionAbstract::getNumberOfParameters — 获取参数数目
获取函数定义的参数数目，包括可选参数
本函数还未编写文档，仅有参数列表。
此函数没有参数。
参数的个数
$reflection = new ReflectionFunction('implode');
echo $reflection->getNumberOfParameters();
Working on a new MVC Application Framework i use this method to check how many arguments are required before calling the sub method!
Example
<?php
$this->method_args_count = $this->CReflection
->getMethod($Route->getMethod())
->getNumberOfParameters();
//Maybe be 5 but if uri is /controller/method/single_param/ we only of 1
$this->params = $Route->getParams(); //0 in some cases
if($this->method_args_count > count($this->params))
{
$this->difference = ($this->method_args_count - count($this->params));
for($i=0;$i<=$this->difference;$i++)
{
$this->params[] = false;
}
}
//Call the method with correct amount of params
// but as false for params that have not been passed!
call_user_func_array(array(new $this->obj,$Route->getMethod()),$this->params);
?>