在Python中将嵌套的JSON转换为CSV文件

Question

我知道这个问题已被多次询问。我尝试了几种解决方案，但是我无法解决我的问题。

我有一个大的嵌套JSON文件（1.4GB），我想使它变平，然后将其转换为CSV文件。

的JSON结构是这样的：

{ 
    "company_number": "12345678", 
    "data": { 
    "address": { 
     "address_line_1": "Address 1", 
     "locality": "Henley-On-Thames", 
     "postal_code": "RG9 1DP", 
     "premises": "161", 
     "region": "Oxfordshire" 
    }, 
    "country_of_residence": "England", 
    "date_of_birth": { 
     "month": 2, 
     "year": 1977 
    }, 
    "etag": "26281dhge33b22df2359sd6afsff2cb8cf62bb4a7f00", 
    "kind": "individual-person-with-significant-control", 
    "links": { 
     "self": "/company/12345678/persons-with-significant-control/individual/bIhuKnFctSnjrDjUG8n3NgOrl" 
    }, 
    "name": "John M Smith", 
    "name_elements": { 
     "forename": "John", 
     "middle_name": "M", 
     "surname": "Smith", 
     "title": "Mrs" 
    }, 
    "nationality": "Vietnamese", 
    "natures_of_control": [ 
     "ownership-of-shares-50-to-75-percent" 
    ], 
    "notified_on": "2016-04-06" 
    } 
} 

我知道，这是很容易与pandas模块来完成，但我不熟悉它。

EDITED

所需的输出应该是这样的：

company_number, address_line_1, locality, country_of_residence, kind, 

12345678, Address 1, Henley-On-Thamed, England, individual-person-with-significant-control 

注意，这仅仅是一个短版。输出应该包含所有的字段。

Answer 1

你可以通过解析JSON结构，只是返回所有的叶子节点列表如下做到这一点：

import json 
import csv 

def get_leaves(item, key=None): 
    if isinstance(item, dict): 
     leaves = [] 
     for i in item.keys(): 
      leaves.extend(get_leaves(item[i], i)) 
     return leaves 
    elif isinstance(item, list): 
     leaves = [] 
     for i in item: 
      leaves.extend(get_leaves(i, key)) 
     return leaves 
    else: 
     return [(key, item)] 


with open('json.txt') as f_input, open('output.csv', 'wb') as f_output: 
    csv_output = csv.writer(f_output) 
    write_header = True 

    for entry in json.load(f_input): 
     leaf_entries = sorted(get_leaves(entry)) 

     if write_header: 
      csv_output.writerow([k for k, v in leaf_entries]) 
      write_header = False 

     csv_output.writerow([v for k, v in leaf_entries]) 

如果你的JSON数据是你给的格式条目列表，然后你应该得到的输出如下：

address_line_1,company_number,country_of_residence,etag,forename,kind,locality,middle_name,month,name,nationality,natures_of_control,notified_on,postal_code,premises,region,self,surname,title,year 
Address 1,12345678,England,26281dhge33b22df2359sd6afsff2cb8cf62bb4a7f00,John,individual-person-with-significant-control,Henley-On-Thames,M,2,John M Smith,Vietnamese,ownership-of-shares-50-to-75-percent,2016-04-06,RG9 1DP,161,Oxfordshire,/company/12345678/persons-with-significant-control/individual/bIhuKnFctSnjrDjUG8n3NgOrl,Smith,Mrs,1977 
Address 1,12345679,England,26281dhge33b22df2359sd6afsff2cb8cf62bb4a7f00,John,individual-person-with-significant-control,Henley-On-Thames,M,2,John M Smith,Vietnamese,ownership-of-shares-50-to-75-percent,2016-04-06,RG9 1DP,161,Oxfordshire,/company/12345678/persons-with-significant-control/individual/bIhuKnFctSnjrDjUG8n3NgOrl,Smith,Mrs,1977 

---

注：如果您使用Python 3.x中，更改以下行：

with open('json.txt', newline='') as f_input, open('output.csv', 'w', newline='') as f_output: