所以我对this theory感兴趣如果你随机访问维基百科文章,重复点击第一个不在括号内的链接,在 95% 的情况下你最终会找到关于 Philosophy 的文章。 .
我想用 Python 编写一个脚本来为我获取链接,最后打印一个很好的列表,其中包含访问过的文章 (linkA -> linkB -> linkC
) 等。
我设法获取了网页的 HTML DOM,并设法去除了一些不必要的链接和引导消歧页面的顶部描述栏。到目前为止,我得出的结论是:
- DOM 以您在某些页面右侧看到的表格开始,例如 Human。 .我们想忽略这些链接。
- 有效的链接元素都有一个
<p>
某处的元素作为他们的祖先(如果它位于<b>
标签或类似标签内,通常是 parent 或祖 parent 。导致消歧页面的顶部栏似乎不包含任何<p>
元素。 - 无效链接包含一些特殊单词后跟冒号,例如
Wikipedia:
到目前为止,还不错。但正是括号让我明白了。在关于 Human 的文章中例如,第一个不在括号内的链接是“/wiki/Species”,但脚本会找到其中的“/wiki/Taxonomy”。
我不知道如何以编程方式解决这个问题,因为我必须在父/子节点的某种组合中查找文本,而这些节点可能并不总是相同的。有什么想法吗?
我的代码可以在下面看到,但这是我编得很快的东西,并不引以为豪。但是,它已被评论,因此您可以看到我的想法(我希望 :))。
"""Wikipedia fun"""
import urllib2
from xml.dom.minidom import parseString
import time
def validWikiArticleLinkString(href):
""" Takes a string and returns True if it contains the substring
'/wiki/' in the beginning and does not contain any of the
"special" wiki pages.
"""
return (href.find("/wiki/") == 0
and href.find("(disambiguation)") == -1
and href.find("File:") == -1
and href.find("Wikipedia:") == -1
and href.find("Portal:") == -1
and href.find("Special:") == -1
and href.find("Help:") == -1
and href.find("Template_talk:") == -1
and href.find("Template:") == -1
and href.find("Talk:") == -1
and href.find("Category:") == -1
and href.find("Bibcode") == -1
and href.find("Main_Page") == -1)
if __name__ == "__main__":
visited = [] # a list of visited links. used to avoid getting into loops
opener = urllib2.build_opener()
opener.addheaders = [('User-agent', 'Mozilla/5.0')] # need headers for the api
currentPage = "Human" # the page to start with
while True:
infile = opener.open('http://en.wikipedia.org/w/index.php?title=%s&printable=yes' % currentPage)
html = infile.read() # retrieve the contents of the wiki page we are at
htmlDOM = parseString(html) # get the DOM of the parsed HTML
aTags = htmlDOM.getElementsByTagName("a") # find all <a> tags
for tag in aTags:
if "href" in tag.attributes.keys(): # see if we have the href attribute in the tag
href = tag.attributes["href"].value # get the value of the href attribute
if validWikiArticleLinkString(href): # if we have one of the link types we are looking for
# Now come the tricky parts. We want to look for links in the main content area only,
# and we want the first link not in parentheses.
# assume the link is valid.
invalid = False
# tables which appear to the right on the site appear first in the DOM, so we need to make sure
# we are not looking at a <a> tag somewhere inside a <table>.
pn = tag.parentNode
while pn is not None:
if str(pn).find("table at") >= 0:
invalid = True
break
else:
pn = pn.parentNode
if invalid: # go to next link
continue
# Next we look at the descriptive texts above the article, if any; e.g
# This article is about .... or For other uses, see ... (disambiguation).
# These kinds of links will lead into loops so we classify them as invalid.
# We notice that this text does not appear to be inside a <p> block, so
# we dismiss <a> tags which aren't inside any <p>.
pnode = tag.parentNode
while pnode is not None:
if str(pnode).find("p at") >= 0:
break
pnode = pnode.parentNode
# If we have reached the root node, which has parentNode None, we classify the
# link as invalid.
if pnode is None:
invalid = True
if invalid:
continue
###### this is where I got stuck:
# now we need to look if the link is inside parentheses. below is some junk
# for elem in tag.parentNode.childNodes:
# while elem.firstChild is not None:
# elem = elem.firstChid
# print elem.nodeValue
print href # this will be the next link
newLink = href[6:] # except for the /wiki/ part
break
# if we have been to this link before, break the loop
if newLink in visited:
print "Stuck in loop."
break
# or if we have reached Philosophy
elif newLink == "Philosophy":
print "Ended up in Philosophy."
break
else:
visited.append(currentPage) # mark this currentPage as visited
currentPage = newLink # make the the currentPage we found the new page to fetch
time.sleep(5) # sleep some to see results as debug
最佳答案
我在 Github (http://github.com/JensTimmerman/scripts/blob/master/philosophy.py) 上找到了一个玩这个游戏的 python 脚本。 它使用 Beautifulsoup 进行 HTML 解析,为了解决括号问题,他只是在解析链接之前删除括号之间的文本。
关于python - 获取维基百科文章中不在括号内的第一个链接,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/10634278/