我正在编写代码,将在Twitter上搜索关键词并将它们存储在python词典中：

        base_url = 'http://search.twitter.com/search.json?rpp=100&q=4sq.com/'
        query = '7bOHRP'
        url_string = base_url + query
        logging.info("url string = " + url_string)
        json_text = fetch(url_string)
        json_response = simplejson.loads(json_text.content)                                              
        result = json_response['results']
        print "Contents"
        print result

结果字典是：

Contents[{
    u 'iso_language_code': u 'en',u 'text': u "I'm at Cafe en Seine (40 Dawson Street,Dublin) w/ 2 others. http://4sq.com/7bOHRP",u 'created_at': u 'Wed,06 Oct 2010 23:37:02 +0000',u 'profile_image_url': u 'http://a1.twimg.com/profile_images/573130785/twitterProfilePhoto_normal.jpg',u 'source': u '<a href="http://foursquare.com" rel="nofollow">foursquare</a>',u 'place': {
        u 'type': u 'neighborhood',u 'id': u '898cf727ca504e96',u 'full_name': u 'Mansion House B,Dublin'
    },u 'from_user': u 'pkeRSSemakers',u 'from_user_id': 60241195,u 'to_user_id': None,u 'geo': None,u 'id': 26597357992,u 'Metadata': {
        u 'result_type': u 'recent'
    }
}]
Status: 200 OK
Content - Type: text / html;charset = utf - 8
Cache - Control: no - cache
Expires: Fri,01 Jan 1990 00: 00: 00 GMT
Content - Length: 0

如何访问’from_user’以及键和值之前的’u’是什么？