Chapter 11 Regex: typo in the code example. Top-level domain validation expression

[nikolayrantsev]

Hello,
Thanks, everyone so much for this course!

1. Found small type in the 11th chapter, section 'Extracting data using regular expressions':
   ...
   Here is our new regular expression:
   [a-zA-Z0-9]\S*@\S*[a-zA-Z]
   ... then the code block with the usage of this example:
   If we use this expression in our program, our data is much cleaner:

# Search for lines that have an at sign between characters
# The characters must be a letter or number
import re
hand = open('mbox-short.txt')
for line in hand:
    line = line.rstrip()
    x = re.findall('[a-zA-Z0-9]\S+@\S+[a-zA-Z]', line)
    if len(x) > 0:
        print(x)

# Code: http://www.py4e.com/code3/re07.py

please update the "+" sign in the line x = re.findall('[a-zA-Z0-9]\S+@\S+[a-zA-Z]', line) with the "*"

2. Interesting thing here is that by running the code with the correct expression [a-zA-Z0-9]\S*@\S*[a-zA-Z], we're receiving the results including lines like:
   [ 'dhorwitz@david-horwitz-6:~/branchManagemnt/sakai_2-5-x']

Appreciate the explanation of how to improve the expression in order to filter out the records not matching email address criteria to have a top-level domain.

Thank you!