Python Json 加载（）返回字符串而不是字典？

Python Json loads() returning string instead of dictionary?

提问by Jade Byfield

I'm trying to do some simple JSON parsing using Python 3's built in JSON module, and from reading a bunch of other questions on SO and googling, it seems this is supposed to be pretty straightforward. However, I think I'm getting a string returned instead of the expected dictionary.

我正在尝试使用 Python 3 的内置 JSON 模块进行一些简单的 JSON 解析，并且通过阅读有关 SO 和谷歌搜索的一堆其他问题，这似乎应该非常简单。但是，我想我得到的是一个字符串而不是预期的字典。

Firstly, here is the JSON I am trying to get values from. It's just some output from Twitter's API

首先，这是我试图从中获取值的 JSON。这只是 Twitter API 的一些输出

[{'in_reply_to_status_id_str': None, 'in_reply_to_screen_name': None, 'retweeted':     False, 'in_reply_to_status_id': None, 'contributors': None, 'favorite_count': 0, 'in_reply_to_user_id': None, 'coordinates': None, 'source': '<a href="http://twitter.com" rel="nofollow">Twitter Web Client</a>', 'geo': None, 'retweet_count': 0, 'text': 'Tweeting a url \nhttp://t.co/QDVYv6bV90', 'created_at': 'Mon Sep 01 19:36:25 +0000 2014', 'entities': {'symbols': [], 'user_mentions': [], 'urls': [{'expanded_url': 'http://www.isthereanappthat.com', 'display_url': 'isthereanappthat.com', 'url': 'http://t.co/QDVYv6bV90', 'indices': [16, 38]}], 'hashtags': []}, 'id_str': '506526005943865344', 'in_reply_to_user_id_str': None, 'truncated': False, 'favorited': False, 'lang': 'en', 'possibly_sensitive': False, 'id': 506526005943865344, 'user': {'profile_text_color': '333333', 'time_zone': None, 'entities': {'description': {'urls': []}}, 'url': None, 'profile_background_image_url': 'http://abs.twimg.com/images/themes/theme1/bg.png', 'profile_background_image_url_https': 'https://abs.twimg.com/images/themes/theme1/bg.png', 'protected': False, 'default_profile_image': True, 'utc_offset': None, 'default_profile': True, 'screen_name': 'KickzWatch', 'follow_request_sent': False, 'following': False, 'profile_background_color': 'C0DEED', 'notifications': False, 'description': '', 'profile_sidebar_border_color': 'C0DEED', 'geo_enabled': False, 'verified': False, 'friends_count': 40, 'created_at': 'Mon Sep 01 16:29:18 +0000 2014', 'is_translator': False, 'profile_sidebar_fill_color': 'DDEEF6', 'statuses_count': 4, 'location': '', 'id_str': '2784389341', 'followers_count': 4, 'favourites_count': 0, 'contributors_enabled': False, 'is_translation_enabled': False, 'lang': 'en', 'profile_image_url': 'http://abs.twimg.com/sticky/default_profile_images/default_profile_6_normal.png', 'profile_image_url_https': 'https://abs.twimg.com/sticky/default_profile_images/default_profile_6_normal.png', 'id': 2784389341, 'profile_use_background_image': True, 'listed_count': 0, 'profile_background_tile': False, 'name': 'Maktub Destiny', 'profile_link_color': '0084B4'}, 'place': None}]

I assigned this String to a variable named json_string like so:

我将此字符串分配给名为 json_string 的变量，如下所示：

json_string = json.dumps(output)
jason = json.loads(json_string)

Then, when I try to get a specific key from the "jason" dictionary:

然后，当我尝试从“jason”字典中获取特定键时：

print(jason['hashtags'])

I'm getting an error:

我收到一个错误：

TypeError: string indices must be integers

I want to be able to convert the json output to a dictionary, then use jason[key_name]call to get values using specified keys. Is there something obvious that I'm missing here?

我希望能够将 json 输出转换为字典，然后使用jason[key_name]call 使用指定的键获取值。有什么明显的东西我在这里失踪了吗？

This is my fist time working with Python, after coming from Java. I absolutely love the language and think it's very powerful. So, any help on this would be greatly appreciated!

这是我从 Java 转过来后第一次使用 Python。我非常喜欢这门语言，并认为它非常强大。因此，对此的任何帮助将不胜感激！

采纳答案by Yep_It's_Me

Ok first you should print your object so that you can read it:

好的，首先你应该打印你的对象以便你可以阅读它：

>>> from pprint import pprint
>>> output = [{'in_reply_to_status_id_str': None, 'in_reply_to_screen_name': None, 'retweeted':     False, 'in_reply_to_status_id': None, 'contributors': None, 'favorite_count': 0, 'in_reply_to_user_id': None, 'coordinates': None, 'source': '<a href="http://twitter.com" rel="nofollow">Twitter Web Client</a>', 'geo': None, 'retweet_count': 0, 'text': 'Tweeting a url \nhttp://t.co/QDVYv6bV90', 'created_at': 'Mon Sep 01 19:36:25 +0000 2014', 'entities': {'symbols': [], 'user_mentions': [], 'urls': [{'expanded_url': 'http://www.isthereanappthat.com', 'display_url': 'isthereanappthat.com', 'url': 'http://t.co/QDVYv6bV90', 'indices': [16, 38]}], 'hashtags': []}, 'id_str': '506526005943865344', 'in_reply_to_user_id_str': None, 'truncated': False, 'favorited': False, 'lang': 'en', 'possibly_sensitive': False, 'id': 506526005943865344, 'user': {'profile_text_color': '333333', 'time_zone': None, 'entities': {'description': {'urls': []}}, 'url': None, 'profile_background_image_url': 'http://abs.twimg.com/images/themes/theme1/bg.png', 'profile_background_image_url_https': 'https://abs.twimg.com/images/themes/theme1/bg.png', 'protected': False, 'default_profile_image': True, 'utc_offset': None, 'default_profile': True, 'screen_name': 'KickzWatch', 'follow_request_sent': False, 'following': False, 'profile_background_color': 'C0DEED', 'notifications': False, 'description': '', 'profile_sidebar_border_color': 'C0DEED', 'geo_enabled': False, 'verified': False, 'friends_count': 40, 'created_at': 'Mon Sep 01 16:29:18 +0000 2014', 'is_translator': False, 'profile_sidebar_fill_color': 'DDEEF6', 'statuses_count': 4, 'location': '', 'id_str': '2784389341', 'followers_count': 4, 'favourites_count': 0, 'contributors_enabled': False, 'is_translation_enabled': False, 'lang': 'en', 'profile_image_url': 'http://abs.twimg.com/sticky/default_profile_images/default_profile_6_normal.png', 'profile_image_url_https': 'https://abs.twimg.com/sticky/default_profile_images/default_profile_6_normal.png', 'id': 2784389341, 'profile_use_background_image': True, 'listed_count': 0, 'profile_background_tile': False, 'name': 'Maktub Destiny', 'profile_link_color': '0084B4'}, 'place': None}]
>>> pprint(output)
[{'contributors': None,
  'coordinates': None,
  'created_at': 'Mon Sep 01 19:36:25 +0000 2014',
  'entities': {'hashtags': [],
               'symbols': [],
               'urls': [{'display_url': 'isthereanappthat.com',
                         'expanded_url': 'http://www.isthereanappthat.com',
                         'indices': [16, 38],
                         'url': 'http://t.co/QDVYv6bV90'}],
               'user_mentions': []},
  'favorite_count': 0,
  'favorited': False,
  'geo': None,
  'id': 506526005943865344,
  'id_str': '506526005943865344',
  'in_reply_to_screen_name': None,
  'in_reply_to_status_id': None,
  'in_reply_to_status_id_str': None,
  'in_reply_to_user_id': None,
  'in_reply_to_user_id_str': None,
  'lang': 'en',
  'place': None,
  'possibly_sensitive': False,
  'retweet_count': 0,
  'retweeted': False,
  'source': '<a href="http://twitter.com" rel="nofollow">Twitter Web Client</a>',
  'text': 'Tweeting a url \nhttp://t.co/QDVYv6bV90',
  'truncated': False,
  'user': {'contributors_enabled': False,
           'created_at': 'Mon Sep 01 16:29:18 +0000 2014',
           'default_profile': True,
           'default_profile_image': True,
           'description': '',
           'entities': {'description': {'urls': []}},
           'favourites_count': 0,
           'follow_request_sent': False,
           'followers_count': 4,
           'following': False,
           'friends_count': 40,
           'geo_enabled': False,
           'id': 2784389341,
           'id_str': '2784389341',
           'is_translation_enabled': False,
           'is_translator': False,
           'lang': 'en',
           'listed_count': 0,
           'location': '',
           'name': 'Maktub Destiny',
           'notifications': False,
           'profile_background_color': 'C0DEED',
           'profile_background_image_url': 'http://abs.twimg.com/images/themes/theme1/bg.png',
           'profile_background_image_url_https': 'https://abs.twimg.com/images/themes/theme1/bg.png',
           'profile_background_tile': False,
           'profile_image_url': 'http://abs.twimg.com/sticky/default_profile_images/default_profile_6_normal.png',
           'profile_image_url_https': 'https://abs.twimg.com/sticky/default_profile_images/default_profile_6_normal.png',
           'profile_link_color': '0084B4',
           'profile_sidebar_border_color': 'C0DEED',
           'profile_sidebar_fill_color': 'DDEEF6',
           'profile_text_color': '333333',
           'profile_use_background_image': True,
           'protected': False,
           'screen_name': 'KickzWatch',
           'statuses_count': 4,
           'time_zone': None,
           'url': None,
           'utc_offset': None,
           'verified': False}}]

From looking at this you can see that output is a listwhich contains a single dict. To access this you need:

从这个看你可以看到输出是一个list包含单个dict. 要访问它，您需要：

>>> first_elem = output[0]

You will also see that the hashtagskey in the first_elemis contained in a second level dictunder the key entities:

您还将看到 中的hashtags键first_elem包含在dict键下的第二级中entities：

>>> entities = first_elem['entities']
>>> pprint(entities)
{'hashtags': [],
 'symbols': [],
 'urls': [{'display_url': 'isthereanappthat.com',
           'expanded_url': 'http://www.isthereanappthat.com',
           'indices': [16, 38],
           'url': 'http://t.co/QDVYv6bV90'}],
 'user_mentions': []}

Now you are able to access hashtags:

现在您可以访问hashtags：

>>> entities['hashtags']
[]

Which just happens to be the empty list.

这恰好是空列表。

To convert to JSON, note the comment:

要转换为 JSON，请注意注释：

>>> import json
>>> # Make sure output is the list object not a string representing the object
>>> json_string = json.dumps(output)
>>> jason = json.loads(output)
>>> jason[0]['entities']['hashtags']
[]

I think your problem is that you made output a string before you json.dumpsit, meaning that json.loadswill return a string, not a json object.

我认为你的问题是你在json.dumps它之前输出了一个字符串，这意味着它json.loads会返回一个字符串，而不是一个 json 对象。

And @Dan's answer is correct, this is not valid JSON. It is however a valid python dict, and I'm assuming that you got it from Twitter using python then printed it.

@Dan 的回答是正确的，这不是有效的 JSON。然而，它是一个有效的 python 字典，我假设你是使用 python 从 Twitter 获得的，然后打印它。

回答by Dan Lenski

First off, your JSON example is not valid JSON; the Twitter API would not output this, because it would break every conforming JSON consumer.

首先，您的 JSON 示例不是有效的 JSON；Twitter API 不会输出这个，因为它会破坏每个符合 JSON 的消费者。

• jsonlintshows the first, obvious syntax error: single-quoted rather than double quoted strings.
• Secondly, you have Nonewhere JSON requires null, Falseinstead of false, and True, instead of true.

• jsonlint显示了第一个明显的语法错误：单引号而不是双引号字符串。
• 其次，您有NoneJSON 需要的地方null，False而不是false，和True，而不是true。

Your alleged "JSON" example appears to have been pre-decoded into Python :). When I use a snippet of real JSON, it works exactly as expected:

您所谓的“JSON”示例似乎已被预解码为 Python :)。当我使用真正的 JSON 片段时，它完全按预期工作：

import json

json_string = r"""
[{"actual_json_key":"actual_json_value"}]
"""

jason = json.loads(json_string)

print(jason[0]["actual_json_key"])