如何向使用 Python 从文件中检索的 JSON 数据添加键值？
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How to add a key-value to JSON data retrieved from a file with Python?
提问by Backo
I am new to Python and I am playing with JSON data. I would like to retrieve the JSON data from a file and add to that data a JSON key-value "on the fly".
我是 Python 新手，正在处理 JSON 数据。我想从文件中检索 JSON 数据，并将 JSON 键值“动态”添加到该数据中。
That is, my json_filecontains JSON data as-like the following:
也就是说，我的json_file包含 JSON 数据如下：
{"key1": {"key1A": ["value1", "value2"], "key1B": {"key1B1": "value3"}}}
I would like to add the "ADDED_KEY": "ADDED_VALUE"key-value part to the above data so to use the following JSON in my script:
我想将"ADDED_KEY": "ADDED_VALUE"键值部分添加到上述数据中，以便在我的脚本中使用以下 JSON：
{"ADDED_KEY": "ADDED_VALUE", "key1": {"key1A": ["value1", "value2"], "key1B": {"key1B1": "value3"}}}
I am trying to write something as-like the following in order to accomplish the above:
我正在尝试编写如下内容以完成上述操作：
import json
json_data = open(json_file)
json_decoded = json.load(json_data)
# What I have to make here?!
json_data.close()
采纳答案by Martijn Pieters
Your json_decodedobject is a Python dictionary; you can simply add your key to that, then re-encode and rewrite the file:
你的json_decoded对象是一个 Python 字典；你可以简单地添加你的密钥，然后重新编码和重写文件：
import json
with open(json_file) as json_file:
json_decoded = json.load(json_file)
json_decoded['ADDED_KEY'] = 'ADDED_VALUE'
with open(json_file, 'w') as json_file:
json.dump(json_decoded, json_file)
I used the open file objects as context managers here (with the withstatement) so Python automatically closes the file when done.
我在这里使用打开的文件对象作为上下文管理器（使用with语句），因此 Python 会在完成后自动关闭文件。
回答by bsoist
You can do
你可以做
json_decoded['ADDED_KEY'] = 'ADDED_VALUE'
OR
或者
json_decoded.update({"ADDED_KEY":"ADDED_VALUE"})
which works nicely if you want to add more than one key/value pair.
如果您想添加多个键/值对，这很有效。
Of course, you may want to check for the existence of ADDED_KEY first - depends on your needs.
当然，您可能想先检查 ADDED_KEY 是否存在 - 取决于您的需要。
AND I assume you want might want to save that data back to the file
而且我假设您可能希望将该数据保存回文件
json.dump(json_decoded, open(json_file,'w'))
回答by 0xff
Json returned from json.loads() behave just like native python lists/dictionaries:
从 json.loads() 返回的 Json 行为就像原生 python 列表/字典：
import json
with open("your_json_file.txt", 'r') as f:
data = json.loads(f.read()) #data becomes a dictionary
#do things with data here
data['ADDED_KEY'] = 'ADDED_VALUE'
#and then just write the data back on the file
with open("your_json_file.txt", 'w') as f:
f.write(json.dumps(data, sort_keys=True, indent=4, separators=(',', ': ')))
#I added some options for pretty printing, play around with them!
For more info check out the official doc
有关更多信息，请查看官方文档
