Question

To begin, I’m working entirely in PHP using the Yii framework, although Yii ultimately has little to do with this question.

I’ve got a class, and inside of it I have an array called $data. I want to filter out certain elements of the array that don’t match up with the parameters I’m sending to the class (I’ll put some syntax below to give you a better idea). I am therefore using array_filter, and it requires one of its inputs to be a comparison function (ie. one that returns true or false for a specific element. Any that cause a ‘false’ to be returned are removed from the array).

The problem is that because the function entered is entered in quotes, I don’t see a way to have the comparison function within the actual class. But when the function is outside of the class, I can’t call the instance variable that I need. So what I really need is to be able to call the instance variable outside of the class somehow, to send the instance variable to the function as a parameter, or to somehow keep the comparison function within the class.

Any ideas on this? The class I mentioned is a widget in Yii. Below is the call to that widget (not that important). The relevant parameter is ‘params’.

$this->widget('application.widgets.CListViewParam', array(
    'dataProvider'=>$dataProvider,
    'itemView'=>'_view',
    'params'=>array('receiverId'=>Yii::app()->user->userId),
));

There is an instance variable within a class in the widget to save the parameter:

public $params = array();

Then there is a call to array_filter and the comparison function:

$data = array_filter($data, "filterData");

The actual comparison function is not important, but below is the skeleton. Remember that it is outside of the class.

function filterData($item) {
    // unable to access $this->params inside of this function!
}

Answer 1

If it’s outside the class and can’t access $this->params, then why not just put it inside the class:

class MyClass {

    public $params;

    public function widget() {
        // ...
        $filtered = array_filter($array, array($this, 'filterData'));
    }

    private function filterData($item) {
       // $this->params is now accessible
    }

}