在 Python 中展平嵌套的 JSON API 字典

Question

我收到了使用以下代码收集的距离矩阵的以下 json 响应：

import requests
import json

payload = {
    "origins": [{"latitude": 54.6565153, "longitude": -1.6802816}, {"latitude": 54.6365153, "longitude": -1.6202816}], #surgery
    "destinations": [{"latitude": 54.6856522, "longitude": -1.2183634}, {"latitude": 54.5393295, "longitude": -1.2623914}, {"latitude": 54.5393295, "longitude": -1.2623914}], #oa - up to 625 entries
    "travelMode": "driving",
    "startTime": "2014-04-01T11:59:59+01:00",
    "timeUnit": "second"
}
headers = {"Content-Length": "497", "Content-Type": "application/json"}
paramtr = {"key": "INSERT_KEY_HERE"}
r = requests.post('https://dev.virtualearth.net/REST/v1/Routes/DistanceMatrix', data = json.dumps(payload), params = paramtr, headers = headers)
data = r.json()["resourceSets"][0]["resources"][0]

并且正在尝试变平：

destinations.latitude、destinations.longitude、origins.latitude、 origins.longitude，departmentTime，destinationIndex，originIndex， totalWalkDuration, travelDistance, travelDuration

来自：

    {'__type': 'DistanceMatrix:http://schemas.microsoft.com/search/local/ws/rest/v1',
 'destinations': [{'latitude': 54.6856522, 'longitude': -1.2183634},
  {'latitude': 54.5393295, 'longitude': -1.2623914},
  {'latitude': 54.5393295, 'longitude': -1.2623914}],
 'errorMessage': 'Request completed.',
 'origins': [{'latitude': 54.6565153, 'longitude': -1.6802816},
  {'latitude': 54.6365153, 'longitude': -1.6202816}],
 'results': [{'departureTime': '/Date(1396349159000-0700)/',
   'destinationIndex': 0,
   'originIndex': 0,
   'totalWalkDuration': 0,
   'travelDistance': 38.209,
   'travelDuration': 3082},
  {'departureTime': '/Date(1396349159000-0700)/',
   'destinationIndex': 1,
   'originIndex': 0,
   'totalWalkDuration': 0,
   'travelDistance': 40.247,
   'travelDuration': 2708},
  {'departureTime': '/Date(1396349159000-0700)/',
   'destinationIndex': 2,
   'originIndex': 0,
   'totalWalkDuration': 0,
   'travelDistance': 40.247,
   'travelDuration': 2708},
  {'departureTime': '/Date(1396349159000-0700)/',
   'destinationIndex': 0,
   'originIndex': 1,
   'totalWalkDuration': 0,
   'travelDistance': 34.857,
   'travelDuration': 2745},
  {'departureTime': '/Date(1396349159000-0700)/',
   'destinationIndex': 1,
   'originIndex': 1,
   'totalWalkDuration': 0,
   'travelDistance': 36.895,
   'travelDuration': 2377},
  {'departureTime': '/Date(1396349159000-0700)/',
   'destinationIndex': 2,
   'originIndex': 1,
   'totalWalkDuration': 0,
   'travelDistance': 36.895,
   'travelDuration': 2377}]}

我目前取得的最好成绩是：

json_normalize(outtie, record_path="results", meta="origins")

但是，这包含嵌套的起点和终点拒绝附加。我还尝试删除该类型以查看它是否有所作为，并探索了 max_level= 和 record_prefix='_' 但无济于事。

Answer 1

我以前遇到过这样的事情，我得到的最好的方法是创建一个 OrderedDict 的递归函数，然后我循环遍历它，所以就在这里。

def flatten(data, sep="_"):
    import collections

    obj = collections.OrderedDict()

    def recurse(temp, parent_key=""):
        if isinstance(temp, list):
            for i in range(len(temp)):
                recurse(temp[i], parent_key + sep + str(i) if parent_key else str(i))
        elif isinstance(temp, dict):
            for key, value in temp.items():
                recurse(value, parent_key + sep + key if parent_key else key)
        else:
            obj[parent_key] = temp

    recurse(data)
    return obj

当您遍历它时，您的数据将如下所示

for key, value in flatten(a).items():
    print(key, value)

destinations_0_latitude 54.6856522
destinations_0_longitude -1.2183634
destinations_1_latitude 54.5393295
destinations_1_longitude -1.2623914
destinations_2_latitude 54.5393295
destinations_2_longitude -1.2623914

我使用分隔符的原因是，它给了你可扩展性，所以你可以使用

key.split("_")

['destinations', '0', 'latitude'] 54.6856522
['destinations', '0', 'longitude'] -1.2183634

之后，您可以轻松地调整语句，例如

if key.split("_")[2] = "latitude":
    do something...

if key.endswith("latitude"):
    do something...

Answer 2

• 我认为这对于flatten_json 来说不是一个合适的问题，但是，它对于构造不够周到的 JSON 对象可能很有用。
  • 有关这些情况，请参阅 How to flatten nested JSON recursively, with flatten_json?。
• destinations 中的list 对应于results 中的list，这意味着，当它们被归一化时，它们将具有相同的索引。
• 数据帧可以正确连接，因为它们会有相应的索引。

# create a dataframe for results and origins
res_or = pd.json_normalize(data, record_path=['results'], meta=[['origins']])

# create a dataframe for destinations
dest = pd.json_normalize(data, record_path=['destinations'], record_prefix='dest_')

# normalize the origins column in res_or
orig = pd.json_normalize(res_or.origins).rename(columns={'latitude': 'origin_lat', 'longitude': 'origin_long'})

# concat the dataframes
df = pd.concat([res_or, orig, dest], axis=1).drop(columns=['origins'])

# display(df)
                departureTime  destinationIndex  originIndex  totalWalkDuration  travelDistance  travelDuration  origin_lat  origin_long  dest_latitude  dest_longitude
0  /Date(1396349159000-0700)/                 0            0                  0          38.209            3082   54.656515    -1.680282      54.685652       -1.218363
1  /Date(1396349159000-0700)/                 1            0                  0          40.247            2708   54.656515    -1.680282      54.539330       -1.262391
2  /Date(1396349159000-0700)/                 2            0                  0          40.247            2708   54.656515    -1.680282      54.539330       -1.262391

更新新的示例数据

• Records 包含destinations 和origins 的索引，因此很容易为每个键创建单独的数据帧，然后为数据帧创建.merge。
  • orig 和dest 的索引对应于results 中的destinationIndex 和originsIndex。

# create three separate dataframe
results = pd.json_normalize(data, record_path=['results'])
dest = pd.json_normalize(data, record_path=['destinations'], record_prefix='dest_')
orig = pd.json_normalize(data, record_path=['origins'], record_prefix='orig_')

# merge them at the appropriate location
df = pd.merge(results, dest, left_on='destinationIndex', right_index=True)
df = pd.merge(df, orig, left_on='originIndex', right_index=True)

# display(df)
                departureTime  destinationIndex  originIndex  totalWalkDuration  travelDistance  travelDuration  dest_latitude  dest_longitude  orig_latitude  orig_longitude
0  /Date(1396349159000-0700)/                 0            0                  0          38.209            3082      54.685652       -1.218363      54.656515       -1.680282
1  /Date(1396349159000-0700)/                 1            0                  0          40.247            2708      54.539330       -1.262391      54.656515       -1.680282
2  /Date(1396349159000-0700)/                 2            0                  0          40.247            2708      54.539330       -1.262391      54.656515       -1.680282
3  /Date(1396349159000-0700)/                 0            1                  0          34.857            2745      54.685652       -1.218363      54.636515       -1.620282
4  /Date(1396349159000-0700)/                 1            1                  0          36.895            2377      54.539330       -1.262391      54.636515       -1.620282
5  /Date(1396349159000-0700)/                 2            1                  0          36.895            2377      54.539330       -1.262391      54.636515       -1.620282