Python和JSON - TypeError列表索引必须是整数而不是str

Question

我正在学习使用Python和API(特别是这个世界杯API,http://www.kimonolabs.com/worldcup/explorer)

JSON数据如下所示:

[
  {
    "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"
  },
   ]

我只是想在这个API中打印所有firstNames.这就是我所拥有的:

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']

但是当我运行它时,我得到错误"......第8行,在...... TypeError:列表索引必须是整数,而不是str"

我已经四处寻找解决方案,但似乎在更深入的"API"问题中找到了问题,我还没有完全理解它,所以对我需要做的任何帮助或解释都会很棒.谢谢!

Answer 1

首先,你应该使用json.loads,而不是json.dumps. loads将JSON源文本转换为Python值,而dumps另一种方式.

修复后,基于问题顶部的JSON片段,readable_json将是一个列表,因此readable_json['firstName']毫无意义.获取'firstName'列表中每个元素的字段的正确方法是消除该playerstuff = readable_json['firstName']行并更改for i in playerstuff:为for i in readable_json:.

Answer 2

我解决了改变

readable_json['firstName']

通过

readable_json[0]['firstName']

Answer 3

您可以将代码简化为

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']

您试图使用字典语法访问列表元素。相当于

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

当您有字典列表并保持嵌套顺序时，这可能会令人困惑。