請問如果要在 [] 中需要 foreach 怎麼辦呢？

$data[] = [
        'name' => $key['add_hour'].':00',
        'data' => [[  
          'x' => (int) $key['add_date'],
          'y' => (int) $key['times']
        ]
        // 這裡面會有多個 x 跟 y]
      ];

像這樣

$data[] = [

    'name' => $key['add_hour'].':00',
    'data' => [[  
      'x' => (int) $key['add_date'],
      'y' => (int) $key['times']
    ],
    [  
      'x' => (int) $key['add_date'],
      'y' => (int) $key['times']
    ],
    [  
      'x' => (int) $key['add_date'],
      'y' => (int) $key['times']
    ]]
  ];