使用Python解析JSON嵌套字典

Question

I have the following nested Dictionary in JSON. If I want to get "id", "self", "name", how should I parse it using a Python Program.

{
  "items": [
    {
      "id": "12345",
      "links": {
        "self": "https://www.google.com"
      },
      "name": "beast",
      "type": "Device"
    }
  ],
  "links": {
    "self": "https://www.google.com"
  },
  "paging": {
    "count": 1,
    "limit": 1,
    "offset": 0,
    "pages": 1
  }
}

Answer 1

To understand how your json is set up, it's easier to break it down. Let's look at the first dictionary's keys, and remove the values.

json = {"items": [], "links": {}}

You have a dictionary with two keys and two values. All three of the variables you are looking for (id, self, name) are in the first key, "items". So let's dive deeper.

json["items"] = [{'links': {'self': 'https://www.google.com'}, 'name': 'beast', 'type': 'Device', 'id': '12345'}]

Now you have a list containing a dictionary with the values you are looking for, so let's enter the first and only value of the list containing the next dictionary.

json["items"][0] = {'links': {'self': 'https://www.google.com'}, 'id': '12345', 'type': 'Device', 'name': 'beast'}

Finally we have the dictionary with the values are looking for, so you can use this code to find name and id.

json["items"][0]["name"] = beast

json["items"][0]["id"] = 12345

The self variable is hidden one dictionary deeper so we have to delve into the links key.

json["items"][0]["links"]["self"] = http://google.com

Now you have all of your values, you just need to follow through all the lists and dictionaries to get the value you want.

Answer 2

It helps to write the dictionary indented, to better view its nesting:

mydict = {   
   'items': [
       {
           'id': '12345',
           'links': {'self': 'https://www.google.com'},
           'name': 'beast',
           'type': 'Device'
       }
    ],
    'links': {'self': 'https://www.google.com'},
    'paging': {
        'count': 1,
        'limit': 1,
        'offset': 0,
        'pages': 1
    }
}

Now you can extract what you want:

If I want to get "id", "self", "name",

print(mydict['items'][0]['id'])
print(mydict['items'][0]['links']['self'])
print(mydict['links']['self'])
print(mydict['items'][0]['name'])

Answer 3

You can write a function, that will get the values you need:

def dict_get(x,key,here=None):
    x = x.copy()
    if here is None: here = []
    if x.get(key):  
        here.append(x.get(key))
        x.pop(key)
    else:
        for i,j in x.items():
          if  isinstance(x[i],list): dict_get(x[i][0],key,here)
          if  isinstance(x[i],dict): dict_get(x[i],key,here)
    return here

dict_get(a,'id')
 ['12345']

dict_get(a,'self')
 ['https://www.google.com', 'https://www.google.com']

dict_get(a,'name')
['beast']

You can as well call any key that you want:

data

a = {
  "items": [
    {
      "id": "12345",
      "links": {
        "self": "https://www.google.com"
      },
      "name": "beast",
      "type": "Device"
    }
  ],
  "links": {
    "self": "https://www.google.com"
  },
  "paging": {
    "count": 1,
    "limit": 1,
    "offset": 0,
    "pages": 1
  }
}

Answer 4

Your json basically contains lists inside it. Jsons are accessed as key value pairs and lists are accessed using indexes.

json_object['items'][0]['id']

The above statement should give you the id. We are accessing the key items, which contains a list. We have [0] because this list contains only one element (which is again a key value pair).

The same approach is followed for self and name

json_object['links']['self']
json_object['items'][0]['links']['self']
json_object['items'][0]['name']

The difference between accessing the two different 'self' bring that one is enclosed in a list hence we need to get into the list and the other one is a dictionary with key 'self' which is inside a dictionary 'links'