在嵌套字典中查找所有键和这些键的键 [英] Find all the keys and keys of the keys in a nested dictionary

问题描述

我正在尝试在Python的嵌套字典中查找数据的所有属性.一些对象的键定义可能具有多个级别.我如何找到这样复杂的嵌套数据的标头(如果我们认为是表结构的话).这是我数据的几行，以查看其外观:

I'm trying to find all the attributes of the data in a nested dictionary in Python. Some objects may have multiple levels in their key definition. How can I find the header of such a complicated nested data (if we think as a table structure). Here are very few lines of my data to see how it looks like:

{"MessageType": "SALES.HOLDCREATED", "Event": {"Id": "ZWbDoMKQw6HDjFzCo8KuwpNmwofCjl7Co8OPwpDCncOSXMOdccKTZVVWZWbCnA==", "RefInfo": {"TId": {"Id": "ZMKXwpbClsOhwpNiw5E="}, "UserId": {"Id": "wpzCksKWwpbCpMKTYsKeZMKZbA=="}, "SentUtc": "2013-04-28T16:59:48.6698042", "Source": 1}, "ItemId": {"Id": 116228}, "Quantity": 1, "ExpirationDate": "2013-04-29T", "Description": null}}
{"MessageType": "SALES.SALEITEMCREATED", "Event": {"Id": "ZWbDoMKQw6HDjFzCo8KuwpNmwofCjl7Co8OPwpDCncOSXMOdccKTwp3CiFZkZMKWwpfCpMKZ", "RefInfo": {"TId": {"Id": "ZGA="}, "UserId": {"Id": "ZMKj"}, "SentUtc": "2013-01-04T", "Source": 1}, "Code": {"Code": "074108235206"}, "Sku": {"Sku": "Con CS54"}}}
{"MessageType": "SALES.SALEITEMCREATED", "Event": {"Id": "ZWbDoMKQw6HDjFzCo8KuwpNmwofCjl7Co8OPwpDCncOSXMOdccKTZcKHVsKcwpjClsKXwqTCmQ==", "RefInfo": {"TId": {"Id": "ZGA="}, "UserId": {"Id": "ZMKj"}, "SentUtc": "2013-01-04T", "Source": 1}, "Code": {"Code": "4000000021"}, "Sku": {"Sku": "NFL-Wallet-MK-2201"}}}

由于此数据首先是Json格式，所以我更改了格式并尝试查找密钥:

Since this data is in Json format first I changed the format and tried to find the key:

import json

data = []
with open("data.raw", "r") as f:
    for line in f:
        data.append(json.loads(line))

for lines in data:
    print(lines.keys())

但是所有行都给了我dict_keys(['Event', 'MessageType']). 我需要的(用于我附加的数据)是一个列表，如:

but it gives me dict_keys(['Event', 'MessageType']) for all the lines. What I need (for this data that I attached) is a list like:

'MessageType' 'Event_Id' 'Event_RefInfo_TId_Id'  'Event_RefInfo_UserId_Id' 'Event_RefInfo_SentUtc' 'Event_RefInfo_Source' 'Event_ItemId_Id' 'Event_ItemId_Quantity' 'Event_ItemId_ExpirationDate'     ...

数据非常大，我只需要找出我拥有的属性即可.

The data is very big and I just need to find out what attributes do I have.

推荐答案

您需要遍历嵌套的字典，您当前的方法只能达到根字典的键.

You'll need to traverse the nested dicts, your current approach only gets as far as the keys of the root dictionary.

您可以使用以下生成器函数查找键并递归遍历嵌套的字典:

You can use the following generator function to find the keys and traverse nested dicts recursively:

import json 
from pprint import pprint

def find_keys(dct):
    for k, v in dct.items():
        if isinstance(v, dict):
            # traverse nested dict
            for x in find_keys(v):
                yield "{}_{}".format(k, x)
        else:
            yield k

给出从您的json对象派生的字典列表，您可以在每个字典中找到键并将它们放在集合中，这样条目是唯一的:

Given a list of dictionaries as derived from your json object, you can find the keys in each dict and put them in a set so entries are unique:

s = set()
for d in json.loads(lst):
    s.update(find_keys(d))

pprint(s)

---

set(['Event_Code_Code',
     'Event_Description',
     'Event_ExpirationDate',
     'Event_Id',
     'Event_ItemId_Id',
     'Event_Quantity',
     'Event_RefInfo_SentUtc',
     'Event_RefInfo_Source',
     'Event_RefInfo_TId_Id',
     'Event_RefInfo_UserId_Id',
     'Event_Sku_Sku',
     'MessageType'])

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