将带有嵌套数组的 JSON 转换为 CSV

Question

这是我的 JSON 模板：

{
  "field 1": [
    {
      "id": "123456"
    },
    {
      "about": "YESH"
    },
    {
      "can_post": true
    },
    {
      "category": "Community"
    }
  ],
  "field 2": [
    {
      "id": "123456"
    },
    {
      "about": "YESH"
    },
    {
      "can_post": true
    },
    {
      "category": "Community"
    }
  ]
}

我想使用 Python 将此 JSON 转换为以下格式的 csv：

0 field 1, id, about, can_post, category

1 field 2, id, about, can_post, category

我尝试使用 pandas 读取_json，然后读取 to_csv，但没有成功。

谢谢

Answer 1

import csv
import json

json.load(json_data) 将json_data（json文档（txt/二进制文件））反序列化为python对象。

with open('jsn.txt','r') as json_data:
    json_dict = json.load(json_data)

由于您的字段名称（将充当字段名称的键）位于不同的字典中，我们必须检查这些字典并将它们放入列表field_names。

field_names = [ 'field']
for d in json_dict['field 1']:
    field_names.extend(d.keys())

with open('mycsvfile.csv', 'w') as f:  
    w = csv.DictWriter(f, fieldnames = fieild_names)
    w.writeheader()

    for k1, arr_v in json_dict.items():
        temp = {k2:v for d in arr_v for k2,v in d.items()}
        temp['field'] = k1
        w.writerow(temp)

输出

field,id,about,can_post,category
field 1,123456,YESH,True,Community
field 2,123456,YESH,True,Community

如果您发现上述 dict 理解令人困惑

      k1  : arr_v 
'field 1' = [{ "id": "123456" },...{"category": "Community"}]

            for d in arr_v:                 
                        k2 : v
               d --> { "id": "123456" }

Answer 2

这个怎么样，如果你有像data这样的json

data = [
   {
    "site": "field1",
    "id": "123456",
    "about": "YESH",
    "can_post": True,
    "category": "Community"
  },
  {
    "site": "field2",
    "id": "123456",
    "about": "YESH",
    "can_post": True,
    "category": "Community"
  }
]
# also use True instead of true

df = pd.DataFrame.from_dict(data)

print(df)
# use df.to_csv('filename.csv') for csv

输出：

  about  can_post   category      id    site
0  YESH      True  Community  123456  field1
1  YESH      True  Community  123456  field2

Answer 3

这里的难点在于你的 json 初始结构不仅仅是一个映射列表，而是一个映射，其中值依次是映射列表。

恕我直言，您必须对输入进行预处理，或逐个元素处理它以获取可以转换为 csv 行的列表或映射。这是一个可能的解决方案：

• 提取第一个元素的键并使用它们构建 DictWriter
• 为每个元素构建一个映射并将其存储在 DictWriter 中

代码可以是：

import json
import csv

# read the json data
with open("input.json") as fd:
    data = json.load(fd)

# extract the field names (using 'field' for the key):
names = ['field']
for d in next(iter(data.values())):
    names.extend(d.keys())

# open the csv file as a DictWriter using those names
with open("output.csv", "w", newline='') as fd:
    wr = csv.DictWriter(fd, names)
    wr.writeheader()
    for field, vals in data.items():
        d['field'] = field
        for inner in vals:
            for k,v in inner.items():
                d[k] = v
        wr.writerow(d)

它给出的数据是：

field,id,about,can_post,category
field 1,123456,YESH,True,Community
field 2,123456,YESH,True,Community