python - Changing Json Data, getting TypeError -

edit: turns out whole problem json had been converted dictionary previously, without me realising. , using json.dumps() instead of .loads() mistake.

original q:i have piece of json code have turned dictionary. retrieving json server. when try access inner values of new dictionary change value, a:

typeerror: string indices must integers, not str 

this code:

corner_data = json.dumps(r.json())  print corner_data  corner_data["geometry"]["corners"] = '{"bottom_right": {"y": "575.531616", "x": "690.547363"}, "top_left": {"y": "-146.739075", "x": "-109.105957"}}' 

turn json string python dict using json.loads (not dumps!):*

corner_data = json.loads(r.json()) 

modify data, assigning python dict (not string!):

corner_data['geometry']['corners'] = {'bottom_right': {'y': '575.531616', 'x': '690.547363'}, 'top_left': {'y': '-146.739075', 'x': '-109.105957'}} 

encode json:

print json.dumps(corner_data) 

* i'm assuming here r.json() returns string. it's entirely possible r.json() decodes json string , returns dict, depends on r is. if that's case, don't need json.loads here, can omit it.