RegExp:如何从Tweets(twitter.com)中提取用户名？

我有以下示例推文:

RT @ user1:谁是@thing和@ user2？

我只想拥有user1,thing和user2.

我可以用什么正则表达式来提取这三个名字？

PS:用户名必须只包含字母,数字和下划线.

测试:

/@([a-z0-9_]+)/i

在Ruby(irb)中:

>> "RT @user1: who are @thing and @user2?".scan(/@([a-z0-9_]+)/i)
=> [["user1"], ["thing"], ["user2"]]

在Python中:

>>> import re
>>> re.findall("@([a-z0-9_]+)", "RT @user1: who are @thing and @user2?", re.I)
['user1', 'thing', 'user2']

在PHP中:

Array
(
    [0] => user1
    [1] => thing
    [2] => user2
)