python json错误：字符串索引必须是整数

Question

Hello when I'm learning python I was blocked by the question below, I've tried some solutions on the site by none of them works so far. When I compile, it returns me: string indices must be integers. Can you help me with that? Thank you.

import json
import urllib

url = raw_input('Enter location: ')
uh = urllib.urlopen(url)
data = uh.read()

print 'Retrieving', url
print 'Retrieved', len(data), 'characters'
info = json.loads(data)
#print 'User count:', len(info)
s = 0

for item in info:
    print item["comments"]["count"]

The url includes something like this

{
  "note":"This file contains the sample data for testing",
  "comments":[
    {
      "name":"Romina",
      "count":97
    },
    {
      "name":"Laurie",
      "count":97
    },
    {
      "name":"Bayli",
      "count":90
    },
    {
      "name":"Siyona",
      "count":90
    },
    {
      "name":"Taisha",
      "count":88
    },
    {
      "name":"Ameelia",
      "count":87
    },}

Answer 1

Your for loop doesn't match the structure of the data.

Try this:

for item in info["comments"]:
    print item["count"]

If you want to see the association of names to counts, try:

for item in info["comments"]:
    print item["name"], item["count"]

If you want to see the names, counts, and their location in that list, try:

for index, item in enumerate(info["comments"]):
    print index, item["name"], item["count"]

Answer 2

You should use print item["comments"][0]["count"] or print item["comments"][1]["count"] and so on. You should use the index of the slice then search for the "count" value from the dicts.

You can, also, use something like this:

for item in info["comments"]:
    print item["count"]

Answer 3

You iterate through every value in parsed dictionary, ie your item s in info are

• "This file contains the sample data for testing"
• [ { "name":"Romina", "count":97 }, { "name":"Laurie", "count":97 }, { "name":"Bayli", "count":90 }, { "name":"Siyona", "count":90 }, { "name":"Taisha", "count":88 }, { "name":"Ameelia", "count":87 }, ... ]

Therefore, in first iteration, you try to get ["comments"]["count"] from the actual string.

If you want to print counts for each comments element, then you should rather: for item in info["comments"]: print item["count"]

The best way of debugging is, just use interpreter (IPython or Jupyter notebooks are very good for this), assign the page to variable, or even create a mock one with the same structure, and then parse it, to verify the correctness of your code. Here the problem is the way the code is being parsed.