public function avg($avg=null)
    {
        $avg = LambdaUtils::toSelectCallable($avg);
        return ($this->sum($avg)/$this->length());
    }
public function avg($avg=null)
    {
        $avg = LambdaUtils::toSelectCallable($avg);
        return ($this->sum($avg)/$this->length());
    }
public function avg ( $ avg = null ) { $ avg = LambdaUtils :: toSelectCallable ( $ avg ) ; return ( $ this -> sum ( $ avg ) / $ this -> length ( ) ) ; }
Find the average of the values from given expression
@param callable|string|null $avg
@return numeric
Find the average of the values from given expression