《python 网络数据采集》这本书中会出现很多这一段代码：
1 from urllib.request import urlopen 2 from bs4 import BeautifulSoup 3 html = urlopen(url) 4 bsobj = BeautifulSoup(html)
我也跟着输入这一段代码，但会出现提示：
UserWarning: No parser was explicitly specified, so I'm using the best available HTML parser for this system ("html.parser"). This usually isn't a problem, but if you run this code on another system, or in a different virtual environment, it may use a different parser and behave differently.
The code that caused this warning is on line 1 of the file <string>. To get rid of this warning, change code that looks like this:
BeautifulSoup(YOUR_MARKUP})
to this:
BeautifulSoup(YOUR_MARKUP, "html.parser")
根据提示，这要把 bsobj = BeautifulSoup(html)，改为bsobj = BeautifulSoup(html，"html.parser")就行了。