What does PHP mean? $ Ctrl-> $ action ();

What does PHP mean? $ Ctrl-& gt; $ action (); $ ctrl-> $ action ();

$ Ctrl is an object. what is access to this object?
--------------------------------------------------------------
The access attribute is $ ctrl-> action;
The usage class is like $ ctrl-> action ();

Reply to discussion (solution)

$ Ctrl-> $ action (); is also the name of a method called, but the name of this method is replaced by a variable $ action.

$ Ctrl-> $ action (); is also the name of a method called, but the name of this method is replaced by a variable $ action.

What does this mean? Could you give me a simple example ??

Function fn (){
Echo 1;
}

$ Fn = 'FN ';
$ Fn ();

It is nothing more than putting the function or object method name variables in and running.
However, we recommend that you use function_exist and method_exist to check

Function fn (){
Echo 1;
}

$ Fn = 'FN ';
$ Fn ();

It is nothing more than putting the function or object method name variables in and running.
However, we recommend that you use function_exist and method_exist to check

Thank you. you can understand it in this way ...~

$ Ctrl-> {$ action} (); actually, the value of the $ action variable is treated as a method of the $ ctrl class.