python和json，Error - TypeError：字符串索引必須是整數

Question

我學習製作android應用的kivy。所以我讀了'在Kivy中創建應用程序'一書。 我按照說明操作時遇到了錯誤。

我的python代碼如下。

from kivy.app import App 
from kivy.uix.boxlayout import BoxLayout 
from kivy.properties import ObjectProperty 
from kivy.network.urlrequest import UrlRequest 
import json 
import urllib 
import urllib.request 
import codecs 

class AddLocationForm(BoxLayout): 

    search_input = ObjectProperty() 
    search_results = ObjectProperty() 


    def search_location(self): 
     search_template = 'http://api.openweathermap.org/data/2.5/' + 'weather?q={}&&APPID=d9733213314ecfdbd08f9753d38444bf' 
     search_url = search_template.format(self.search_input.text) 
     u = urllib.request.urlopen(search_url) 
     data = u.read().decode('utf-8') 
     print(type(data)) 
     # request = UrlRequest(search_url, self.found_location) 
     self.found_location(data) 

    def found_location(self, data): 
     # reader = codecs.getreader("utf-8") 
     data2 = json.loads(data) 
     # data2 = reader(data).json() 
     print(data2) 
     for i in data2: 
      cities = ['{} ({})'.format(i['name'],i['sys']['country'])] 
      self.search_results.item_strings = cities 

class WeatherApp(App): 
    pass 

if __name__ == '__main__': 
    WeatherApp().run() 

我的錯誤是

Traceback (most recent call last): 
    File "E:\Weather\main.py", line 52, in <module> 
    WeatherApp().run() 
    File "C:\Python34\lib\site-packages\kivy\app.py", line 828, in run 
runTouchApp() 
    File "C:\Python34\lib\site-packages\kivy\base.py", line 487, in runTouchApp 
    EventLoop.window.mainloop() 
    File "C:\Python34\lib\site-packages\kivy\core\window\window_sdl2.py", line 619, in mainloop 
    self._mainloop() 
    File "C:\Python34\lib\site-packages\kivy\core\window\window_sdl2.py", line 362, in _mainloop 
    EventLoop.idle() 
    File "C:\Python34\lib\site-packages\kivy\base.py", line 330, in idle 
    self.dispatch_input() 
    File "C:\Python34\lib\site-packages\kivy\base.py", line 315, in dispatch_input 
    post_dispatch_input(*pop(0)) 
    File "C:\Python34\lib\site-packages\kivy\base.py", line 221, in post_dispatch_input 
    listener.dispatch('on_motion', etype, me) 
    File "kivy\_event.pyx", line 718, in kivy._event.EventDispatcher.dispatch (kivy\_event.c:7699) 
    File "C:\Python34\lib\site-packages\kivy\core\window\__init__.py", line 1030, in on_motion 
    self.dispatch('on_touch_down', me) 
    File "kivy\_event.pyx", line 718, in kivy._event.EventDispatcher.dispatch (kivy\_event.c:7699) 
    File "C:\Python34\lib\site-packages\kivy\core\window\__init__.py", line 1046, in on_touch_down 
    if w.dispatch('on_touch_down', touch): 
    File "kivy\_event.pyx", line 718, in kivy._event.EventDispatcher.dispatch (kivy\_event.c:7699) 
    File "C:\Python34\lib\site-packages\kivy\uix\widget.py", line 432, in on_touch_down 
    if child.dispatch('on_touch_down', touch): 
    File "kivy\_event.pyx", line 718, in kivy._event.EventDispatcher.dispatch (kivy\_event.c:7699) 
    File "C:\Python34\lib\site-packages\kivy\uix\widget.py", line 432, in on_touch_down 
    if child.dispatch('on_touch_down', touch): 
    File "kivy\_event.pyx", line 718, in kivy._event.EventDispatcher.dispatch (kivy\_event.c:7699) 
    File "C:\Python34\lib\site-packages\kivy\uix\behaviors\button.py", line 110, in on_touch_down 
    self.dispatch('on_press') 
    File "kivy\_event.pyx", line 714, in kivy._event.EventDispatcher.dispatch (kivy\_event.c:7654) 
    File "kivy\_event.pyx", line 1224, in kivy._event.EventObservers.dispatch (kivy\_event.c:13497) 
    File "kivy\_event.pyx", line 1108, in kivy._event.EventObservers._dispatch (kivy\_event.c:12329) 
    File "C:\Python34\lib\site-packages\kivy\lang.py", line 1557, in  custom_callback 
    exec(__kvlang__.co_value, idmap) 
    File "E:\Weather\weather.kv", line 89, in <module> 
on_press: root.search_location() 
    File "E:\Weather\main.py", line 35, in search_location 
self.found_location(data) 
    File "E:\Weather\main.py", line 43, in found_location 
    cities = ['{} ({})'.format(i['name'],i['sys']['country'])] 
TypeError: string indices must be integers 

和JSON內容

{ 
"coord":{"lon":-123.12,"lat":49.25}, 
"weather":[{"id":800,"main":"Clear","description":"clearsky","icon":"02n"}], 
"base":"stations", 
"main":{"temp":265.29,"pressure":1022,"humidity":73,"temp_min":263.15,"temp_max":267.15 }, 
"visibility":48279, 
"wind":{"speed":2.6,"deg":80},"clouds":{"all":5},"dt":1484230500, 
"sys":{"type":1,"id":3359,"message":0.0149,"country":"CA","sunrise":1484237006,"sunset":1484267964}, 
"id":6173331,"name":"Vancouver","cod":200} 

我該如何解決呢？

Answer 1

你正在做一個字符串的指數之，不是說你以爲你是字典，這裏

for i in data2: 
    cities = ['{} ({})'.format(i['name'],i['sys']['country'])] 
    self.search_results.item_strings = cities 

正如在評論中提到tdelaney，你是通過迭代字典，然後試圖採取它內部的字符串的指示。

另請參閱this post。

Answer 2

你只得到1個記錄作爲字典，所以你不需要循環。

def found_location(self, data): 
    # reader = codecs.getreader("utf-8") 
    data2 = json.loads(data) 
    # data2 = reader(data).json() 
    print(data2) 
    cities = ['{} ({})'.format(data2['name'],data2['sys']['country'])] 
    self.search_results.item_strings = cities