数组到字符串转换 - 变量函数名称调用

Question

I need to call some functions inside a class; based on variables, something like this:

$x->$y();

But, I found a strange behavior, consider the following sample code:

$arr = array(

    "some_index" => "func_name"
);


$str = "func_name";

class some_class {

    public function func_name() {

        echo "It works in class!";
    }
}

$some_obj = new some_class();

$some_obj->$arr['some_index']();
$some_obj->$str();

Now the line

$some_obj->$arr['some_index']();

gives the errors:

Array to string conversion in ...
Undefined property: some_class::$Array in ...
Uncaught Error: Function name must be a string in...

But, the line

$some_obj->$str();

works perfectly.

Also, both the lines will work, if the function is not defined inside a class.

Anyone knows why this is happening ?

Answer 1

You should call it this way:

$some_obj->{$arr['some_index']}();

here's a living example