How to make function argument optional in PHP?

Question

Suppose following is my function definition:

public function addPhotoFeed($val)
{
-----------------------------
------------------------------
-----------------------------
}

In above function $val is an array that is passed as an argument to the same.

Now I want to call the above function when I don't pass any argument. So how should I call it?

Answer 1

Simply assign the parameter to null, so like this.

public function addPhotoFeed($val = null)
{
 //TODO
}

You will be able to call the function with or without parameters

addPhotoFeed();
addPhotoFeed("Something");

If you don't want the function to do anything when its called with a null parameter, then you could add a condition inside the function, something like this.

public function addPhotoFeed($val = null)
{
   if($vall == null)
     // Do nothing
   else
     // Do something
}