<?php

class Foo
{

    public function bar()
    {
        return array_map(array($this, 'mapper'), array(1, 2, 3));
    }


    private function mapper($i)
    {
        return $i + 1;
    }

}


$foo = new Foo();
var_dump($foo->bar()); // array(2, 3, 4);