Python and JSON - TypeError list indices must be integers not str

Question

I am learning to use Python and APIs (specifically, this World Cup API, http://www.kimonolabs.com/worldcup/explorer)

The JSON data looks like this:

[
  {
    "firstName": "Nicolas Alexis Julio",
    "lastName": "N'Koulou N'Doubena",
    "nickname": "N. N'Koulou",
    "assists": 0,
    "clubId": "5AF524A1-830C-4D75-8C54-2D0BA1F9BE33",
    "teamId": "DF25ABB8-37EB-4C2A-8B6C-BDA53BF5A74D",
    "id": "D9AD1E6D-4253-4B88-BB78-0F43E02AF016",
    "type": "Player"
  },

 {
    "firstName": "Alexandre Dimitri",
    "lastName": "Song-Billong",
    "nickname": "A. Song",
    "clubId": "35BCEEAF-37D3-4685-83C4-DDCA504E0653",
    "teamId": "DF25ABB8-37EB-4C2A-8B6C-BDA53BF5A74D",
    "id": "A84540B7-37B6-416F-8C4D-8EAD55D113D9",
    "type": "Player"
  },
   ]

I am simply trying to print all of the firstNames in this API. Here's what I have:

import urllib2
import json

url = "http://worldcup.kimonolabs.com/api/players?apikey=xxx"
json_obj = urllib2.urlopen(url).read
readable_json = json.dumps(json_obj)
playerstuff = readable_json['firstName']
for i in playerstuff:
    print i['firstName']

But when I run it, I get the error "...line 8, in ...TypeError: list indices must be integers, not str"

I have looked around for solutions, but seem to find questions to more "in depth" API questions and I don't really understand it all yet, so any help or explanation as to what I need to do would be amazing. Thank you!

Answer 1

First of all, you should be using json.loads, not json.dumps. loads converts JSON source text to a Python value, while dumps goes the other way.

After you fix that, based on the JSON snippet at the top of your question, readable_json will be a list, and so readable_json['firstName'] is meaningless. The correct way to get the 'firstName' field of every element of a list is to eliminate the playerstuff = readable_json['firstName'] line and change for i in playerstuff: to for i in readable_json:.

Answer 2

I solved changing

readable_json['firstName']

by

readable_json[0]['firstName']

Answer 3

You can simplify your code down to

url = "http://worldcup.kimonolabs.com/api/players?apikey=xxx"
json_obj = urllib2.urlopen(url).read
player_json_list = json.loads(json_obj)
for player in readable_json_list:
    print player['firstName']

You were trying to access a list element using dictionary syntax. the equivalent of

foo = [1, 2, 3, 4]
foo["1"]

It can be confusing when you have lists of dictionaries and keeping the nesting in order.