PYTHON 1. We will perform the same task using the HTMLParser tool. When properly

Question

PYTHON

1. We will perform the same task using the HTMLParser tool. When properly working, the program should be given a URL, and print (to the console) all of the headlines on the page.

In order to do this, we will need to write all 3 handler methods for HTMLParser. Here is a brief description of what each should do:

handle_startag: Checks the tag to see if it is a headline tag (<h1>, <h2>, or <h3>). We will not concern ourselves with a threshold for this assignment. If the tag is a headline tag, then a flag is set to True in order to indicate that a headline element has been found. This is necessary for the handle_data method to extract the headline.

handle_data: Check the flag set by handle_starttag to see if we are in a headline element. If so, the the headline should be printed.

handle_endtag: Sets the flag back to False, indicating that we are no longer in a headline element.

from urllib.request import *
from urllib.error import *
from html.parser import *
from urllib.parse import urljoin

class Headlines(HTMLParser):

    def __init__(self, url):
        HTMLParser.__init__(self)
        self.url = url
        self.tag = None
        self.f = open('headlines.html','w')
      
   

def handle_starttag(self, tag, attrs):
        if tag in ['h1', 'h2', 'h3']:
            pass   # REPLACE THIS      
   

def handle_data(self, data):
        if self.tag != None:
            pass   # REPLACE THIS
          

    def handle_endtag(self, tag):
        if tag in ['h1', 'h2', 'h3']:
            pass # REPLACE THIS

def headlines(self):
        contents = urlopen(self.url).read().decode()
        self.feed(contents)
        self.f.close()

Explanation / Answer

from urllib.request import *
from urllib.error import *
from html.parser import *
from urllib.parse import urljoin
class Headlines(HTMLParser):
def __init__(self, url):
HTMLParser.__init__(self)
self.url = url
self.tag = None
self.f = open('headlines.html','w')
  

def handle_starttag(self, tag, attrs):
if tag in ['h1', 'h2', 'h3']:
flag=True
return flag

def handle_data(self, data):
if self.tag != None:
if flag==True:
print(data)
  
def handle_endtag(self, tag):
if tag in ['h1', 'h2', 'h3']:
flag=False
return flag   

def headlines(self):
contents = urlopen(self.url).read().decode()
self.feed(contents)
self.f.close()

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