从 json 文件中读取嵌套数据

Question

I am trying to read the nested data of a json file, particularly in the example below I want to read both of the "pose" tags of -each- frame until the end. When I try to reach them using the script below:

expjsonFiles = glob.glob(expFilesPath + '*.json')

for expjsonFile in expjsonFiles[:-1]:
    jsonfpath = os.path.abspath(expjsonFile)
    jsonfname = os.path.basename(jsonfpath)

    with open(jsonfpath, 'r') as jsonf:
        json_data = jsonf.read()

    #parse json file
    obj = json.loads(json_data)
    #print(str(obj['label']))
    label = str(obj['label'])

    for data in obj['frame_index']:
        print(data['pose'])

I get the error:

    for data in obj['skeleton']['frame_index']:
KeyError: 'skeleton'

and when I try this:

for data in obj['data']['frame_index']:
        print(data['pose'])

It says

for data in obj['data']['skeleton']['frame_index']:
TypeError: list indices must be integers or slices, not str

Sample json file:

{
  "data": [
    {
      "frame_index": 1,
      "skeleton": [
        {
          "pose": [
            0.2203125,
            0.2546875,
            0.271875,
            0.2421875,
            0.303125,
            0.240625,
            0.3296875,
            0.2421875,
            0.3390625,
            0.2796875
          ],
          "score": [
            1,
            1,
            1,
            1,
            1
          ]
        },
        {
          "pose": [
            0.2203125,
            0.2546875,
            0.271875,
            0.2421875,
            0.303125,
            0.240625,
            0.3296875,
            0.2421875,
            0.3390625,
            0.2796875
          ],
          "score": [
            1,
            1,
            1,
            1,
            1
          ]
        }
      ]
    },
    {
      "frame_index": 2,
      "skeleton": [
        {
          "pose": [
            0.2203125,
            0.2546875,
            0.271875,
            0.2421875,
            0.303125,
            0.240625,
            0.3296875,
            0.2421875,
            0.3390625,
            0.2796875
          ],
          "score": [
            1,
            1,
            1,
            1,
            1
          ]
        },
        {
          "pose": [
            0.2203125,
            0.2546875,
            0.271875,
            0.2421875,
            0.303125,
            0.240625,
            0.3296875,
            0.2421875,
            0.3390625,
            0.2796875
          ],
          "score": [
            1,
            1,
            1,
            1,
            1
          ]
        }
      ]
    },
    {
      "frame_index": 3,
      "skeleton": [
        {
          "pose": [
            0.2203125,
            0.2546875,
            0.271875,
            0.2421875,
            0.303125,
            0.240625,
            0.3296875,
            0.2421875,
            0.3390625,
            0.2796875
          ],
          "score": [
            1,
            1,
            1,
            1,
            1
          ]
        },
        {
          "pose": [
            0.2203125,
            0.2546875,
            0.271875,
            0.2421875,
            0.303125,
            0.240625,
            0.3296875,
            0.2421875,
            0.3390625,
            0.2796875
          ],
          "score": [
            1,
            1,
            1,
            1,
            1
          ]
        }
      ]
    }
  ],
  "label": "G1",
  "label_index": 0
}

Answer 1

Given the json you provide, this would be the path you should use to address the issue:

import pandas as pd

data = {"data": [{"frame_index": 1, "skeleton": [{"pose": [0.2203125,0.2546875,0.271875,0.2421875,0.303125,0.240625,0.3296875,0.2421875,0.3390625,0.2796875], "score": [1,1,1,1,1]},{"pose": [0.2203125, 0.2546875,0.271875,0.2421875,0.303125,0.240625,0.3296875,0.2421875,0.3390625,0.2796875], "score": [1,1,1,1,1]}]},{"frame_index": 2, "skeleton": [{"pose": [0.2203125,0.2546875,0.271875,0.2421875,0.303125,0.240625,0.3296875,0.2421875,0.3390625,0.2796875], "score": [1,1,1,1,1]},{"pose": [0.2203125, 0.2546875,0.271875,0.2421875,0.303125,0.240625,0.3296875,0.2421875,0.3390625,0.2796875], "score": [1,1,1,1,1]}]},{"frame_index": 3, "skeleton": [{"pose": [0.2203125,0.2546875,0.271875,0.2421875,0.303125,0.240625,0.3296875,0.2421875,0.3390625,0.2796875], "score": [1,1,1,1,1]},{"pose": [0.2203125, 0.2546875,0.271875,0.2421875,0.303125,0.240625,0.3296875,0.2421875,0.3390625,0.2796875], "score": [1,1,1,1,1]}]}],"label": "G1", "label_index": 0}

for i in range(len(data['data'])):
    for j in range(len(data['data'][i]['skeleton'])):
        print(data['data'][i]['skeleton'][j]['pose'])

Remember, jsons can be treated as dictionaries that contain dictionaries and lists within them, therefore you can simply address them as such.

Output:

[0.2203125, 0.2546875, 0.271875, 0.2421875, 0.303125, 0.240625, 0.3296875, 0.2421875, 0.3390625, 0.2796875]
[0.2203125, 0.2546875, 0.271875, 0.2421875, 0.303125, 0.240625, 0.3296875, 0.2421875, 0.3390625, 0.2796875]
[0.2203125, 0.2546875, 0.271875, 0.2421875, 0.303125, 0.240625, 0.3296875, 0.2421875, 0.3390625, 0.2796875]
[0.2203125, 0.2546875, 0.271875, 0.2421875, 0.303125, 0.240625, 0.3296875, 0.2421875, 0.3390625, 0.2796875]
[0.2203125, 0.2546875, 0.271875, 0.2421875, 0.303125, 0.240625, 0.3296875, 0.2421875, 0.3390625, 0.2796875]
[0.2203125, 0.2546875, 0.271875, 0.2421875, 0.303125, 0.240625, 0.3296875, 0.2421875, 0.3390625, 0.2796875]

Answer 2

You unpack your json wrong. The value of 'data' is a list. So you need to iterate over it. Moreover, each element in it contains a list under a name 'skeleton' :

    for data_element in obj['data']:
        print(data_element['frame_index'])
        for pose_element in data_element['skeleton']:
            print(pose_element['pose'])

Answer 3

You can do this:

data = {"data": [{"frame_index": 1, "skeleton": [{"pose": [0.2203125,0.2546875,0.271875,0.2421875,0.303125,0.240625,0.3296875,0.2421875,0.3390625,0.2796875], "score": [1,1,1,1,1]},{"pose": [0.2203125, 0.2546875,0.271875,0.2421875,0.303125,0.240625,0.3296875,0.2421875,0.3390625,0.2796875], "score": [1,1,1,1,1]}]},{"frame_index": 2, "skeleton": [{"pose": [0.2203125,0.2546875,0.271875,0.2421875,0.303125,0.240625,0.3296875,0.2421875,0.3390625,0.2796875], "score": [1,1,1,1,1]},{"pose": [0.2203125, 0.2546875,0.271875,0.2421875,0.303125,0.240625,0.3296875,0.2421875,0.3390625,0.2796875], "score": [1,1,1,1,1]}]},{"frame_index": 3, "skeleton": [{"pose": [0.2203125,0.2546875,0.271875,0.2421875,0.303125,0.240625,0.3296875,0.2421875,0.3390625,0.2796875], "score": [1,1,1,1,1]},{"pose": [0.2203125, 0.2546875,0.271875,0.2421875,0.303125,0.240625,0.3296875,0.2421875,0.3390625,0.2796875], "score": [1,1,1,1,1]}]}],"label": "G1", "label_index": 0}

for dict_rows in data["data"]:
    for skeleton in dict_rows['skeleton']:
        print(skeleton['pose'])