error json

[snippsat]

Look at:

halo = json.loads(j)
print(halo)
# json.loads() should give back a python dictionary
print(type(halo))

for user in halo: will loop over key in dictionary,not both key and values.
It's now a string you try to get key from not a dictionary,just to make your error.

>>> s = 'foo'
>>> s['faceAttributes']
Traceback (most recent call last):
  File "<interactive input>", line 1, in <module>
TypeError: string indices must be integers

# So a string need integer,but this is not what you want
>>> s[0]
'f'