如何序列化Python列表中的JSON密鑰？

Question

我想使用Python遍歷JSON文件並打印一組鍵。

例如：

import json 

KEYS_TO_PRINT = ["id", "channel.title"] 
my_data = {"items": [{"id": 1, "channel": {"channelid": "channelid1", "title": "nailed_it1"}}, {"id": 2, "channel": {"channelid": "channelid2", "title": "nailed_it2"}}]} 
this_row = [] 

for item in my_data["items"]: 
    for key in KEYS_TO_PRINT: 
     try: 
      if "." in key: 
       split_up = key.split(".") 
       print item[split_up[0]][split_up[1]] 
      else: 
       print item[key] 
     except KeyError: 
      print "Oops" 

然而，這是很醜陋的。有沒有更好的方法？

Answer 1

考慮這樣的事情，你可以使用「。」來指定一個子鍵。劃定您的密鑰。這裏有一個例子：

KEYS_TO_EXPORT = ["id", "dateTime", "title", "channel.title"] 
item = {"id": 1, "channel": {"title": "nailed_it"}} 
this_row = [] 
for export_key in KEYS_TO_EXPORT: 
    try: 
     value = item 
     for key in export_key.split("."): 
      value = value[key] 
     this_row.append(str(value).encode('utf-8')) 
    except KeyError: 
     this_row.append("") 

編輯與工作清單：

該解決方案可以輕鬆地進行擴展，項目按編輯原來的問題如下列表工作。我也轉向使用.get，像Will在評論中所建議的那樣。

KEYS_TO_PRINT = ["id", "channel.title"] 
my_data = {"items": [ 
    {"id": 1, "channel": {"channelid": "channelid1", "title": "nailed_it1"}}, 
    {"id": 2, "channel": {"channelid": "channelid2", "title": "nailed_it2"}}, 
    {"id": 3} 
]} 
this_row = [] 

for item in my_data["items"]: 
    for export_key in KEYS_TO_PRINT: 
     value = item 
     for key in export_key.split("."): 
      value = value.get(key) 
      if value == None: break 
     this_row.append(str(value).encode('utf-8') if value != None else "") 
print this_row