Extracting certain data from json

Question

https://www.huobi.com/p/api/contents/

hello, i want to extract all the title from this api and see if there are any changes in the title.. how can i do it with python?

i am getting this error:

before_set = before['data']['items']['title']
TypeError: list indices must be integers or slices, not str

---

here is my code:

import requests
import json

try:
    with open('notice.json', 'r') as current_notice:
        before = json.loads(current_notice.read())
except IOError:
    before = requests.get('https://www.huobi.com/p/api/contents/').json()
    with open('notice.json', 'w') as current_notice:
        current_notice.write(json.dumps(before))
    print("First run....")

after = requests.get('https://www.huobi.com/p/api/contents/').json()

before_set = before['data']['items']['title']
after_set = after['data']['items']['title']

new_set = after_set - before_set

while True:
    try:
        if not new_set:
            print("No change... Exiting.")
        if new_set:
            print("There are changes")
    except Exception as e:
        print(e)
        pass            

Answer 1

The data contained in before['data']['items'] is a list. You would access the first item's title using:

before['data']['items'][0]['title']

To get all titles, you can use a list comprehension:

before_set = [item['title'] for item in before['data']['items']]

Answer 2

you have list with ids for best visualization i recommended you compare data with id, for example:

bitems = before.get('data', {}).get('items', [])
before_data = [(item.get('id'), item.get('title')) for item in bitems]
aitems = after.get('data', {}).get('items', [])
after_data = [(item.get('id'), item.get('title')) for item in aitems]

compare = set(before_data) ^ set(after_data)
print(compare)

Answer 3

The issue here is that response['data']['items'] comes out as a list

type(response['data']['items'])
<class 'list'>

You can use list comprehension to get around this or try default dicts from collections

Answer 4

this is because before['data']['items'] has multiple items and therefore it returns an array

you can iterate over the list like:

for item in before['data']['items']:
  print item['title']

or you just can save all titles into a variable like:

titles = [item['title'] for item in before['data']['items']]