python-TypeError: string indices must be integers. How to fix?

Question

I'm querying Google+ data with TF-IDF and save the data as a JSONfile. While working with this file I get an error.

Code

import json
import nltk

DATA = 'C:/Users/Dung Ring/Desktop/kpdl/107033731246200681024.json'
data = json.loads(open(DATA).read())

QUERY_TERMS = ['SOPA']

activities = [activity['object']['content'].lower().split() \
          for activity in data \
            if activity['object']['content'] != " "]

# TextCollection provides tf, idf, and tf_idf abstractions so 
# that we don't have to maintain/compute them ourselves

tc = nltk.TextCollection(activities)

relevant_activities = []

for idx in range(len(activities)):
    score = 0
    for term in [t.lower() for t in QUERY_TERMS]:
        score += tc.tf_idf(term, activities[idx])
    if score > 0:
         relevant_activities.append({'score': score, 'title': data[idx]['title'],
                          'url': data[idx]['url']})

# Sort by score and display results

relevant_activities = sorted(relevant_activities, key=lambda p: p['score'],    reverse=True)
for activity in relevant_activities:
      print activity['title']
      print '\tLink: %s' % (activity['url'], )
      print '\tScore: %s' % (activity['score'], )
      print

Error message

Traceback (most recent call last):
  File "ex9.py", line 11, in <module>
    if activity['object']['content']!= ""]
TypeError: string indices must be integers

I use Python 2.7.

Answer 1

Either activity or activity['object'] is a string and not a dictionary as you expect. Print data and check.