迭代JSON对象

Question

我试图迭代一个JSON对象来导入数据,即标题和链接.我似乎无法获得过去的内容:.

JSON:

[
    {
        "title": "Baby (Feat. Ludacris) - Justin Bieber",
        "description": "Baby (Feat. Ludacris) by Justin Bieber on Grooveshark",
        "link": "http://listen.grooveshark.com/s/Baby+Feat+Ludacris+/2Bqvdq",
        "pubDate": "Wed, 28 Apr 2010 02:37:53 -0400",
        "pubTime": 1272436673,
        "TinyLink": "http://tinysong.com/d3wI",
        "SongID": "24447862",
        "SongName": "Baby (Feat. Ludacris)",
        "ArtistID": "1118876",
        "ArtistName": "Justin Bieber",
        "AlbumID": "4104002",
        "AlbumName": "My World (Part II);\nhttp://tinysong.com/gQsw",
        "LongLink": "11578982",
        "GroovesharkLink": "11578982",
        "Link": "http://tinysong.com/d3wI"
    },
    {
        "title": "Feel Good Inc - Gorillaz",
        "description": "Feel Good Inc by Gorillaz on Grooveshark",
        "link": "http://listen.grooveshark.com/s/Feel+Good+Inc/1UksmI",
        "pubDate": "Wed, 28 Apr 2010 02:25:30 -0400",
        "pubTime": 1272435930
    }
]

我尝试使用字典:

def getLastSong(user,limit):
    base_url = 'http://gsuser.com/lastSong/'
    user_url = base_url + str(user) + '/' + str(limit) + "/"
    raw = urllib.urlopen(user_url)
    json_raw= raw.readlines()
    json_object = json.loads(json_raw[0])

    #filtering and making it look good.
    gsongs = []
    print json_object
    for song in json_object[0]:   
        print song

此代码仅在之前打印信息:.(忽略贾斯汀比伯赛道 :))

Answer 1

我相信你可能意味着:

for song in json_object:
    # now song is a dictionary
    for attribute, value in song.iteritems():
        print attribute, value # example usage

注意:使用song.items而不是song.iteritemsPython 3.

Answer 2

您加载JSON数据有点脆弱.代替:

json_raw= raw.readlines()
json_object = json.loads(json_raw[0])

你应该真的这样做:

json_object = json.load(raw)

你不应该想到你得到的"JSON对象".你有一个清单.该清单包含两个词组.dicts包含各种键/值对,所有字符串.当你这样做时json_object[0],你要求列表中的第一个字典.当你迭代它时for song in json_object[0]:,你会迭代dict的键.因为这是你在迭代dict时得到的.如果要访问与该dict中的键关联的值,则可以使用,例如,json_object[0][song].

这些都不是特定于JSON的.它只是基本的Python类型,其基本操作在任何教程中都有介绍.

Answer 3

这个问题已经存在很长时间了,但我想贡献一下我通常迭代JSON对象的方式.在下面的示例中,我展示了一个包含JSON的硬编码字符串,但JSON字符串可以很容易地来自Web服务或文件.

import json

def main():

    # create a simple JSON array
    jsonString = '{"key1":"value1","key2":"value2","key3":"value3"}'

    # change the JSON string into a JSON object
    jsonObject = json.loads(jsonString)

    # print the keys and values
    for key in jsonObject:
        value = jsonObject[key]
        print("The key and value are ({}) = ({})".format(key, value))

    pass

if __name__ == '__main__':
    main()

Answer 4

反序列化JSON后,你有一个python对象.使用常规对象方法.

在这种情况下,您有一个由字典组成的列表:

json_object[0].items()

json_object[0]["title"]

等等

Answer 5

我会更像这样解决这个问题

import json
import urllib2

def last_song(user, limit):
    # Assembling strings with "foo" + str(bar) + "baz" + ... generally isn't 
    # as nice as using real string formatting. It can seem simpler at first, 
    # but leaves you less happy in the long run.
    url = 'http://gsuser.com/lastSong/%s/%d/' % (user, limit)

    # urllib.urlopen is deprecated in favour of urllib2.urlopen
    site = urllib2.urlopen(url)

    # The json module has a function load for loading from file-like objects, 
    # like the one you get from `urllib2.urlopen`. You don't need to turn 
    # your data into a string and use loads and you definitely don't need to 
    # use readlines or readline (there is seldom if ever reason to use a 
    # file-like object's readline(s) methods.)
    songs = json.load(site)

    # I don't know why "lastSong" stuff returns something like this, but 
    # your json thing was a JSON array of two JSON objects. This will 
    # deserialise as a list of two dicts, with each item representing 
    # each of those two songs.
    #
    # Since each of the songs is represented by a dict, it will iterate 
    # over its keys (like any other Python dict). 
    baby, feel_good = songs

    # Rather than printing in a function, it's usually better to 
    # return the string then let the caller do whatever with it. 
    # You said you wanted to make the output pretty but you didn't 
    # mention *how*, so here's an example of a prettyish representation
    # from the song information given.
    return "%(SongName)s by %(ArtistName)s - listen at %(link)s" % baby

Answer 6

对于 Python 3，您必须解码从 Web 服务器返回的数据。例如我将数据解码为 utf8 然后处理它：

    # example of json data object group with two values of key id
    jsonstufftest = '{"group": {"id": "2", "id": "3"}}
    # always set your headers
    headers = {"User-Agent": "Moz & Woz"}
    # the url you are trying to load and get json from
    url = "http://www.cooljson.com/cooljson.json"
    # in python 3 you can build the request using request.Request 
    req = urllib.request.Request(url, None, headers)
    # try to connect or fail gracefully
    try:
        response = urllib.request.urlopen(req) # new python 3 code -jc
    except:
        exit('could not load page, check connection')
    # read the response and DECODE
    html=response.read().decode('utf8') # new python3 code
    # now convert the decoded string into real JSON
    loadedjson = json.loads(html)
    # print to make sure it worked
    print (loadedjson) # works like a charm
    # iterate through each key value
    for testdata in loadedjson['group']:
        print (accesscount['id']) # should print 2 then 3 if using test json

如果不解码，Python 3 中将出现字节与字符串错误。