mongodb in codeigniter, debug problem

in some_code.php

---

$query = new MongoCode('
    function (index, val开发者_StackOverflowue){
        .... 
         // I need to check some value of some_variable in here
         // etc ) some_variable = 1 or "abc"
        ....
    }
');
$run = $this->db->command($query);

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How could I print mongodb variables in php?

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var_dump() is always your friend.