浏览词典列表并仅选择存在键的行

Question

如何搜索词典列表,只选择存在某个键的行(无论值是多少)？例如,在这三行中,我只想保留那些"userid"存在的位置(最后两个).

[{'long': None, 'tweetid': None, 'timestamp': None, 'lat': None},
 {'userid': '113503286', 'long': '-87.624387', 'tweetid': '595084326489956352', 'timestamp': '1430714134224', 'lat': '41.852653'}, 
 {'userid': '2421024865', 'long': '-87.629798', 'tweetid': '595084376632729600', 'timestamp': '1430714146179', 'lat': '41.878114'}]

我尝试了以下代码,但是收到错误:

datum = [ row for row in data if row['tweet_time'] in row]
Traceback (most recent call last):
File "<pyshell#102>", line 1, in <module>
datum = [ row for row in data if ['tweet_time'] in row]

Answer 1

[row for row in data if row['tweet_time'] in row]

不.但是几乎.dict如果密钥存在,检查包含检查.

[row for row in data if 'userid' in row]