Question

我有一个具有以下结构的json文件：

[{
"field1": "first",
"field2": "d",
"id": 35,
"features": [
    {
        "feature_id": 2,
        "value": 6
    },
    {
        "feature_id": 3,
        "value": 8.5
    },
    {
      "feature_id":5,
      "value":6.7
    },
    {
    "feature_id":10,
    "value": 3.4
    }
  ],
  "time": "2018-11-17"
},
{
"field1": "second",
"field2": "b",
"id": 36,
"features": [
    {
        "feature_id": 3,
        "value": 5.4
    },
    {
        "feature_id": 10,
        "value": 9.5
    },

  ],
  "time": "2018-11-17"
}]

我可以将其更改为Pandas Dataframe

import json
import pandas as pd
with open(file) as json_data:
 data = json.load(json_data)

df=pd.DataFrame(data)

，但是一列在列表中具有嵌套的字典，因此features列包含具有字典列表的列。我想整理全部数据，因此最终表应如下所示。感谢任何帮助吗？

Final_dataframe

Answer 1

Json被[]更改为有效：

data = [{
"field1": "first",
"field2": "d",
"id": 35,
"features": [
    {
        "feature_id": 2,
        "value": 6
    },
    {
        "feature_id": 3,
        "value": 8.5
    },
    {
      "feature_id":5,
      "value":6.7
    },
    {
    "feature_id":10,
    "value": 3.4
    }
  ],
  "time": "2018-11-17"
},
{
"field1": "second",
"field2": "b",
"id": 36,
"features": [
    {
        "feature_id": 3,
        "value": 5.4
    },
    {
        "feature_id": 10,
        "value": 9.5
    },

  ],
  "time": "2018-11-17"
}]

然后循环每个项目并为features创建新的字典对象，最后一遍是DataFrame的构造者：

L = []
for x in data:
    d = {}
    for k, v in x.items():
        if k == 'features':
            for y in v:
                d[f"feature_id_{y['feature_id']}"] = y['value']
        else:
            d[k] = v
    L.append(d)

df = pd.DataFrame(L)
print (df)
   feature_id_10  feature_id_2  feature_id_3  feature_id_5  field1 field2  id  \
0            3.4           6.0           8.5           6.7   first      d  35   
1            9.5           NaN           5.4           NaN  second      b  36   

         time  
0  2018-11-17  
1  2018-11-17

Answer 2

对于具有嵌套键的扁平化JSON对象成单个Dict，请使用以下函数。

def flatten_json(nested_json):
"""
    Flatten json object with nested keys into a single level.
    Args:
        nested_json: A nested json object.
    Returns:
        The flattened json object if successful, None otherwise.
"""
out = {}

def flatten(x, name=''):
    if type(x) is dict:
        for a in x:
            flatten(x[a], name + a + '_')
    elif type(x) is list:
        i = 0
        for a in x:
            flatten(a, name + str(i) + '_')
            i += 1
    else:
        out[name[:-1]] = x

flatten(nested_json)
return out

希望此功能对您有帮助。

将一列带有嵌套词典的json文件转换为Pandas Dataframe

2 个答案: