Python Network data Acquisition II

First, regular expression

* Table matches 0 or more times a*b*

+ Table at least once

[] Match any one

() identify a group

{m,n} m or n times

[^] matches any characters that are not in brackets

| Indicate or

. Indicates a match for any character

^ Start of the table character ^a to start with a

\ means escape character

$ and ^ opposite starts at the end of the string

？！ does not contain

Second, get the attribute

Get all the properties of a label

Mytag.attrs

Get the resource location of the picture SRC

myimgtag.attrs["SRC"]

To get a Web page function:

Random.seed (Datetime.datetime.now ())
def getlinks (Articleurl):
html = Urlopen ("http://en.wikipedia.org" +articleurl)
BS0BJ = BeautifulSoup (HTML)
return Bs0bj.find ("div", {"id": "bodycontent"}). FindAll ("A", Herf=re.compile ("^ (/wiki/)" (?!:).) *$"))
Links = getlinks ("/wiki/kevin_bacon")
While Len (links) > 0:
Newarticle = Links[random.randint (0,len (links)-1)].attrs["href"]
Print (newarticle)
link = getlinks (newarticle)

Python Network data Acquisition II