Combining duplicate key and value pairs in json using python

I want to combine duplicate key and value pairs in JSON dictionaries. I am having trouble doing that. As other keys are not the same and are repetitive. I have the following JSON format:

[
   {
      "date":"2018-12-01",
      "9":{
         "mean":{
            "x_axis":-0.71,
            "y_axis":8.75,
            "z_axis":5.23
         }
      }
   },
   {
      "date":"2018-12-02",
      "4":{
         "mean":{
            "x_axis":-0.76,
            "y_axis":7.83,
            "z_axis":2.63
         }
      }
   },
   {
      "date":"2018-12-02",
      "5":{
         "mean":{
            "x_axis":0.59,
            "y_axis":6.46,
            "z_axis":7.12
         }
      }
   },
   {
      "date":"2018-12-02",
      "10":{
         "mean":{
            "x_axis":1.07,
            "y_axis":9.46,
            "z_axis":0.08
         }
      }
   }
]

But I want the following JSON format:

[
   {
      "date":"2018-11-22",
      "1":{
         "mean":{
            "x_axis":3.11,
            "y_axis":3.22,
            "z_axis":3.33
         }
      },
      "2":{
         "mean":{
            "x_axis":2.11,
            "y_axis":2.22,
            "z_axis":2.33
         }
      }
   },
   {
      "date":"2018-11-23",
      "1":{
         "mean":{
            "x_axis":3.11,
            "y_axis":3.22,
            "z_axis":3.33
         }
      },
      "2":{
         "mean":{
            "x_axis":2.11,
            "y_axis":2.22,
            "z_axis":2.33
         }
      }
   }
]

See that the same date key and values do not repeat. If the date is the same all other keys are under it. Please help!

You can identify your unique dates first and use that to create new dictionaries

# list_of_dicts is defined as list of dictionaries from your json file

dates = set([d['date'] for d in list_of_dicts])   # unique dates
dicts_by_date = [[d for d in list_of_dicts if d['date'] == date] for date in dates]  # create sublists based on date

new_list = [{k: v for d in ds for k, v in d.items()} for ds in dicts_by_date]

Output:

[
    {
        'date': '2018-12-01',
        '9': {'mean': {'x_axis': -0.71, 'y_axis': 8.75, 'z_axis': 5.23}}
    },
    {
        'date': '2018-12-02',
        '4': {'mean': {'x_axis': -0.76, 'y_axis': 7.83, 'z_axis': 2.63}},
        '5': {'mean': {'x_axis': 0.59, 'y_axis': 6.46, 'z_axis': 7.12}},
        '10': {'mean': {'x_axis': 1.07, 'y_axis': 9.46, 'z_axis': 0.08}}
    }
]