我需要实现接受颜色作为字符串参数的函数，并将其作为json_encode返回

Question

I want to get the function that can accept a string parameter and return it to json format. for example if i call $ballcolor->getBall("orange"); then the output// should be: { "color":"orange", "ball": ["basketball"]}

and if a call does not have any color for that ball: { "color":"black", "ball": []}

class BallColor
    {
      private $ballcolor;

      function BallColor($ballcolor)
      {
        $this->ballcolor = $ballcolor;
      }

      public function getBall($color)
      {

        return NULL;

      }
    }

    $ballcolor = new BallColor(array(
        "orange" => array("basketball"),
        "white" => array("football")
    ));

    echo $ballcolor->getBall("orange");
    echo "
";
    echo $ballcolor->getBall("black");