beautifulsoup导航树

from urllib.request import urlopen
from bs4 import BeautifulSoup

html = urlopen("http://www.pythonscraping.com/pages/page3.html")
bsObj = BeautifulSoup(html,"lxml")
print("==================child=================================")         #子标签
for child in bsObj.find("table",{"id":"giftList"}).children:
    print(child)

print("=================descendant=================================")         #后代标签
for descendant in bsObj.find("table",{"id":"giftList"}).descendants:
    print(descendant)

print("==================sibling==================================")             #兄弟标签
for sibling in bsObj.find("table",{"id":"giftList"}).tr.next_siblings:
    print(sibling)

print("==================parent==================================")      #父标签
print(bsObj.find("img",{"src":"../img/gifts/img1.jpg"}).parent.previous_sibling.get_text())