所以我有这个python代码，我从维基百科页面获得1000个节点，三个深度，每页10个节点。
import urllib.request as urllib2
html = urllib2.urlopen('https://en.wikipedia.org/wiki/Computer_science').read()
from bs4 import BeautifulSoup
soup = BeautifulSoup(html, "lxml")
#first depth = list1
for link in soup.find_all('a', href=True, title=True)[:10]:
print(link['href'])
#second depth = list2
sub_html = urllib2.urlopen('https://en.wikipedia.org' + link['href'])
sub_soup = BeautifulSoup(sub_html, "lxml")
for sub_link in sub_soup.find_all('a', href=True, title=True)[:10]:
print(sub_link['href'])
#third depth = list3
sub_sub_html = urllib2.urlopen('https://en.wikipedia.org' + link['href'])
sub_sub_soup = BeautifulSoup(sub_sub_html, "lxml")
for sub2_link in sub_sub_soup.find_all('a', href=True, title=True)[:10]:
print(sub2_link['href'])
接下来，我需要保存边文件中的所有节点。我的形式是：
“edge_from_list1”， “edge_from_list2”;
“edge_from_list1”， “edge_from_list2”;
.......
“edge_from_list2”， “edge_from_list3”
“edge_from_list2”， “edge_from_list3”
...
任何人都可以给我一个提示，我该怎么做？