python和json，错误-TypeError：字符串索引必须为整数

Question

I Learn kivy for making android app. so I read the 'Creating Apps in Kivy' book. I encountered into error when I follow instructions.

My python code is below.

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()

And my Error is

 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

And json content is

{
"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}

How can I solve it??

Answer 1

You are only getting 1 record as a dict so you don't need the loop.

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

Answer 2

You're taking the indice of a string, not the dictionary that you think you are, here

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

As tdelaney mentioned in the comments, you're iterating through the dict and then trying to take the indice of a string inside of it.

See this post as well.