xml-extraction.py

# The program will prompt for a URL, 
# read the XML data from that URL using urllib 
# and then parse and extract the comment counts from the XML data, 
# compute the sum of the numbers in the file and enter the sum

import urllib.request, urllib.parse, urllib.error
import xml.etree.ElementTree as ET
import ssl

# Ignore SSL certificate errors
ctx = ssl.create_default_context()
ctx.check_hostname = False
ctx.verify_mode = ssl.CERT_NONE

while True:
    try: # prompt the user for a url location and read it with urllib
        url = input('Enter location: ')
        xml = urllib.request.urlopen(url, context=ctx).read()
        break
    except: # prevent invalid urls from crashing the program
        print('Invalid url. Try again.')
        continue

print('Retrieving', url) # let the user know retrieval was successful
print('Retrieved', len(xml), 'characters') # get the total number of characters in the file

# Parse the comments in the XML data
tree = ET.fromstring(xml) # get the xml element tree
lst = tree.findall('comments/comment') # place all comment tags in a list
print('Comment count:', len(lst)) # get the total number of comment tags

# Extract the counts and add them together
sum = 0 # initalize a sum variable
for item in lst: # go through each comment item in the list
    count = item.find('count').text # retrieve the count text
    sum += int(count) # compute the sum of the extracted counts

print('The sum of all comments is:', sum)