解析嵌套的JSON数据

Question

This JSON output is from a MongoDB aggregate query. I essentially need to parse the nested data JSON down to the following to the ' total' and '_id' values.

{
'ok': 1.0, 
'result': [
            {
                'total': 142250.0, 
                '_id': 'BC'
            }, 
            {
                'total': 210.88999999999996,
                 '_id': 'USD'
            }, 

            {
                'total': 1065600.0, 
                '_id': 'TK'
            }
            ]
}

I've tried 5 different techniques to get what I need from it, however I've run into issues using the json and simplejson modules.

Ideally, the output will be something like this:

142250.0, BC
210.88999999999996, USD
1065600.0, TK

Answer 1

NOTE: Your JSON response from MongoDB is not actually valid. JSON requires double-quotes ( " ), not single-quotes ( ' ).

I'm not sure why your response has single-quotes instead of double-quotes but from the looks of it you can replace them and then just use the built-in json module:

from __future__ import print_function
import json

response = """{
    'ok': 1.0, 
    'result': [
        {
            'total': 142250.0, 
            '_id': 'BC'
        }, 
        {
            'total': 210.88999999999996,
             '_id': 'USD'
        }, 

        {
            'total': 1065600.0, 
            '_id': 'TK'
        }
        ]
}"""

# JSON requires double-quotes, not single-quotes.
response = response.replace("'", '"')
response = json.loads(response)
for doc in response['result']:
    print(doc['_id'], doc['total'])

Answer 2

Your example text is not valid JSON text . JSON string must start with a " quotation mark , not ' ; but it seems a valid Python literal that you can parse with ast.literal_eval() function :

import ast

data = ast.literal_eval(input_string)
for item in data["result"]:
    print("{total}, {_id}".format(**item))

Output

142250.0, BC
210.89, USD
1065600.0, TK

A better way might be to fix the querying process to get valid JSON and use json module to parse it.

Answer 3

The response you are getting from the mongodb seems to be the compatible to put for the dictionary type object. as

{
    'ok': 1.0,  'result': [
        {
            'total': 142250.0, 
            '_id': 'BC'
        }, 
        {
            'total': 210.88999999999996,
             '_id': 'USD'
        }, 
        {
            'total': 1065600.0, 
            '_id': 'TK'
        }
    ]
}

Instead of putting it into multiline string and replacing single quotes in double quotes, can't we directly assign it to the dict type object. and perform further operation on it like:

json_data = {
    'ok': 1.0,
    'result':
        [
            {
                'total': 142250.0,
                '_id': 'BC'
            },
            {
                'total': 210.88999999999996,
                '_id': 'USD'
            },
            {
                'total': 1065600.0,
                '_id': 'TK'
            }
    ]
}

And:

for data in json_data['result']:
    print(data['total'], data['_id'])

Answer 4

import json

data = json.loads(mongo_db_json)
result = data['result']
for value_dict in result:
    print '{0}, {1}'.format(value['total'], value['_id'])

This should work

Answer 5

This should do.

import json

def parse_json(your_json):
    to_dict = json.loads(your_json)
    for item in to_dict['results']:
        print item['total']