Python HTML Resolution Demo

1. SGMLParser:

　　这里定义了一个Parse类，继承SGMLParser里面的方法。使用一个变量is_h4做标记判定html文件中的h4标签，如果遇到h4标签，则将标签内的内容加入到Parse的变量name中。解释一下start_h4()和end_h4()函数，他们原型是SGMLParser中的

start_tagname(self, attrs)
end_tagname(self)

tagname就是标签名称，比如当遇到<h4>，就会调用start_h4，遇到</h4>，就会调用 end_h4。attrs为标签的参数，以[(attribute, value), (attribute, value), ...]的形式传回。

Demo:

 #!/usr/bin/python2.7
 # FileName: sgmlparser.py
 # Author: lxw
 # Date: 2015-07-30
     
 import urllib2
 from sgmllib import SGMLParser
         
 class Parse(SGMLParser):
     def __init__(self):
         SGMLParser.__init__(self)
         self.is_h4 = ""
         self.name = []
         self.is_a = ""
         self.link = []
         
     def start_h4(self, attrs):
         self.is_h4 = 1
         
     def end_h4(self):
         self.is_h4 = ""                                                           
         
     def start_a(self, attrs):
         self.is_a = 1
         
     def end_a(self):
         self.is_a = ""
             
     def handle_data(self, text):
         if self.is_h4 == 1:
             self.name.append(text)
         if self.is_a == 1:
             self.link.append(text)
     
 def main():
     #content = urllib2.urlopen("https://kb.isc.org/").read()
     content = urllib2.urlopen("https://list.taobao.com/browse/cat-0.htm").read()
     parse = Parse()
     parse.feed(content)
     for item in parse.link:
         print(item.decode("gbk").encode("utf-8"))
     print("-"*20)
     for item in parse.name:
         print(item.decode("gbk").encode("utf-8"))
 
 
 if __name__ == '__main__':
     main()
 else:
     print("Being imported as a module.")

2. PyQuery: 

#!/usr/bin/python2.7
 #coding=utf-8
 #如果想有中文注释就必须得有上面的语句
 # FileName: pyQueryParse.py
 # Author: lxw
 # Date: 2015-07-30
 
 from pyquery import PyQuery
 '''
 直接运行没有问题, 但当把输出重定向到文件时, 就出现如下错误:
 UnicodeEncodeError: 'ascii' codec can't encode characters in position 166-167:     ordinal not in range(128)
 解决方法是增加下面的三行代码:
 '''
 import sys 
 reload(sys)
 sys.setdefaultencoding("utf-8")
 
 def main():
     source = PyQuery(url="https://list.taobao.com/browse/cat-0.htm")
     #print(type(source))    #<class 'pyquery.pyquery.PyQuery'>
     #print(type((source("a"))))  #<class 'pyquery.pyquery.PyQuery'>
     for data in source.find("a"):
         #print(type(data))   #<class 'lxml.html.HtmlElement'>
         #print(type(PyQuery((data))))   #<class 'pyquery.pyquery.PyQuery'>
         #print(type(PyQuery(data).text())) #<type 'unicode'>/<type 'str'>
         print(PyQuery(data).text())                                               
 
 if __name__ == '__main__':
     main()
 else:
     print("Being imported as a module.")

References:

Python写爬虫——抓取网页并解析HTML

python数据抓取之pyquery包