遇到一个编程问题，你必须首先想到的是要简化它，简化成一个最简单的问题后，写最简单的代码来解决它，同时只付出最简单的测试代价。
简单HTML源码：
1<!--The loneliest number--> <a>2<!--Can be as bad as one--><b>3
提取上述代码中的注释：
from bs4 import BeautifulSoup, Comment
soup = BeautifulSoup("""1<!--The loneliest number-->
<a>2<!--Can be as bad as one--><b>3""")
comments = soup.findAll(text=lambda text:isinstance(text, Comment))
for comment in comments:
print comment
输出结果：
The loneliest number Can be as bad as one
去掉上面HTML代码中的注释：
from bs4 import BeautifulSoup, Comment
soup = BeautifulSoup("""1<!--The loneliest number-->
<a>2<!--Can be as bad as one--><b>3""")
comments = soup.findAll(text=lambda text:isinstance(text, Comment))
[comment.extract() for comment in comments]
print soup
输出结果：
1 <a>2<b>3</b></a>
参考：
1、How to find the comment tag <!--…--> with BeautifulSoup?
2、BeautifulSoup documentation #Removing elements
原文：http://my.oschina.net/ioslighter/blog/423166