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Python Json加载（）返回字符串而不是字典？

[英]Python Json loads() returning string instead of dictionary?

 原文  2014-09-01 22:26:19  8   3    python/ json/ parsing/ dictionary

问题描述

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.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。 However, I think I'm getting a string returned instead of the expected dictionary.但是，我认为我得到的是返回的字符串而不是预期的字典。

Firstly, here is the JSON I am trying to get values from.首先，这是我试图从中获取值的 JSON。 It's just some output from Twitter's API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一个名为 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.我希望能够将 json 输出转换为字典，然后使用jason[key_name]调用来使用指定的键获取值。 Is there something obvious that I'm missing here?我在这里有什么明显的遗漏吗？

This is my fist time working with Python, after coming from Java.这是我从 Java 毕业后第一次使用 Python。 I absolutely love the language and think it's very powerful.我非常喜欢这种语言，并认为它非常强大。 So, any help on this would be greatly appreciated!因此，非常感谢您对此的任何帮助！

3 个解决方案

解决方案1
 22 已采纳  2014-09-01 23:05:53

Ok first you should print your object so that you can read it:好的，首先您应该打印您的对象，以便您可以阅读它：

>>> 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 list which contains a single dict .通过查看这个，您可以看到输出是一个包含单个dict的list 。 To access this you need:要访问它，您需要：

>>> first_elem = output[0]

You will also see that the hashtags key in the first_elem is contained in a second level dict under the key entities :您还将看到first_elem hashtags包含在键entities下的第二级dict中：

>>> 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.dumps it, meaning that json.loads will return a string, not a json object.我认为您的问题是您在json.dumps之前输出了一个字符串，这意味着json.loads将返回一个字符串，而不是一个 json 对象。

And @Dan's answer is correct, this is not valid JSON. @Dan 的回答是正确的，这不是有效的 JSON。 It is however a valid python dict, and I'm assuming that you got it from Twitter using python then printed it.然而，它是一个有效的 python 字典，我假设你使用 python 从 Twitter 获得它然后打印它。

解决方案2
 7  2014-09-01 23:00:31

First off, your JSON example is not valid JSON;首先，您的 JSON 示例不是有效的 JSON； the Twitter API would not output this, because it would break every conforming JSON consumer. Twitter API 不会输出这个，因为它会破坏每个符合标准的 JSON 消费者。

  • jsonlint shows the first, obvious syntax error: single-quoted rather than double quoted strings. 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。
  • Secondly, you have None where JSON requires null , False instead of false , and True , instead of true .其次，您有None ，其中 JSON 需要null 、 False代替false和True代替true 。

Your alleged "JSON" example appears to have been pre-decoded into Python :).您所谓的“JSON”示例似乎已被预解码为 Python :)。 When I use a snippet of real JSON, it works exactly as expected:当我使用一段真实的 JSON 时，它的工作原理完全符合预期：

import json

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

jason = json.loads(json_string)

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

解决方案3
 3  2021-09-18 13:45:06

I did json.loads(json.loads(string)) and was able to get the dictionary.我做了json.loads(json.loads(string))并且能够得到字典。 You can check it out.你可以检查一下。 The first time it doesn't just return the same string, but processes it (eg removes \\ characters).第一次它不仅返回相同的字符串，而且处理它（例如删除\\字符）。

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