Extract a nested list from this JSON object with Python

Question

I'm using this python script (in an attempt) to extract a nested list from a JSON object.

import json
from collections import defaultdict
from pprint import pprint

with open('data-science.txt') as data_file:
    data = json.load(data_file)

locations = defaultdict(int)

for item in data['included']:
    location = item['attributes']
    print(location)

I get the following output:

{'name': 'Victoria', 'coord': [51.503378, -0.139134]}
{'name': 'United Kingdom', 'coord': None}
{'name': 'data science'}
{'CEO': None, 'abbreviation': None, 'logoUrl': None, 'title': 'Make IT London'}
{'name': 'Victoria', 'coord': [51.503378, -0.139134]}
{'name': 'United Kingdom', 'coord': None}
{'name': 'data science'}
{'CEO': None, 'abbreviation': None, 'logoUrl': None, 'title': 'Make IT London'}
{'name': 'Victoria', 'coord': [51.503378, -0.139134]}
{'name': 'United Kingdom', 'coord': None}
{'name': 'data science'}
{'CEO': None, 'abbreviation': None, 'logoUrl': None, 'title': 'Make IT London'}
{'name': 'Victoria', 'coord': [51.503378, -0.139134]}
{'name': 'United Kingdom', 'coord': None}
{'name': 'data science'}
{'CEO': None, 'abbreviation': None, 'logoUrl': None, 'title': 'Make IT London'}
{'name': 'Victoria', 'coord': [51.503378, -0.139134]}
{'name': 'United Kingdom', 'coord': None}
{'name': 'data mining'}
{'name': 'data analysis'}

But really what I want is the 'coord' list associated with an "id".

A single record looks like this:

    {
        "id": 3,
        "type": "location",
        "attributes": {
            "name": "Victoria",
            "coord": [
                51.503378,
                -0.139134
            ]
        }
    },

How can I extract the only the "id": 3 and "coord": [ 51.503378, -0.139134 ]?

I've removed this link from the question, as the content within has been deleted. Please try to add examples directly to questions, to avoid external link breakage. — halfer
– halfer, Commented Jan 23, 2018 at 10:34

jimf · Accepted Answer · 2016-11-30 18:32:11Z

2

This is a little bare-bones but may help. Baseline - you might want to use the get function in python. (See this: https://docs.python.org/2/library/stdtypes.html#dict.get)

I won't expand too much on the below code - it is fairly simple - but you can add some logic around it to check if id is None or if coord is None and do additional processing for your own purposes.

for record in data['included']:
    id = record.get('id', None)
    coord = record.get('attributes', {}).get('coord', None)

answered Nov 30, 2016 at 18:32

jimf

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2 Comments

smatthewenglish Over a year ago

how would it be possible to output the name too?

jimf Over a year ago

You would use the same pattern - record.get('attributes', {}).get('name', None)

Daniel · Accepted Answer · 2016-11-30 18:29:31Z

1

You have to access the sub-structure with its key:

coords = {}
for item in data['included']:
    coords[item['id']] = item['attributes']['coords']

answered Nov 30, 2016 at 18:29

Daniel

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Comments

wwii · Accepted Answer · 2016-11-30 18:36:54Z

0

>>> data
{'id': 3, 'attributes': {'coord': [51.503378, -0.139134], 'name': 'Victoria'}, 'type': 'location'}
>>> from operator import itemgetter
>>> my_id = itemgetter('id')
>>> attributes = itemgetter('attributes')
>>> coord = itemgetter('coord')
>>> 
>>> my_id(data), coord(attributes(data))
(3, [51.503378, -0.139134])
>>> {my_id(data) : coord(attributes(data))}
{3: [51.503378, -0.139134]}
>>> d = {}
>>> d[my_id(data)] = coord(attributes(data))
>>> d
{3: [51.503378, -0.139134]}
>>>

answered Nov 30, 2016 at 18:36

wwii

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Comments

mrehan · Accepted Answer · 2016-11-30 19:24:16Z

0

I am assuming, the id and type are always provided through JSON response, and if type is location then coord will be given too:

location_map = {}

for item in data.get('included', [])
    if item['type'] == 'location':
        location_map[item['id']] = item['attributes']['coord']

print location_map

OR in more pythonic way:

location_map = {
    item['id']: item['attributes']['coord']
    for item in data.get('included', []) if item['type'] == 'location'
}
print location_map

For sample input:

[
  {
    "id": 3,
    "type": "location",
    "attributes": {
        "name": "Victoria",
        "coord": [
            51.503378,
            -0.139134
        ]
     }
  }
]

result would be:

{3: [51.503378, -0.139134]}

For reference see Dict Comprehensions: https://www.python.org/dev/peps/pep-0274/

edited Nov 30, 2016 at 19:24

answered Nov 30, 2016 at 18:44

mrehan

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4 Comments

smatthewenglish Over a year ago

:/ I don't understand how that would fit in the code.

mrehan Over a year ago

I've seen the JSON response coord will only be present on the items that are having type equals to 'location'. So, you just have to replace your location with what I've provided (i.e. location_map). I don't think there is any rocket science in this. for reference see dict comprehensions: python.org/dev/peps/pep-0274

mrehan Over a year ago

@s.matthew.english did you get it?

mrehan Over a year ago

@s.matthew.english, updated my answer with another way of achieving the same outcome.

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