Python and Regex: Problem with re findall() - python-3.x

Question

This is a project found # https://automatetheboringstuff.com/2e/chapter7/
It searches text on the clipboard for phone numbers and emails then copy the results to the clipboard again.
If I understood it correctly, when the regular expression contains groups, the findall() function returns a list of tuples. Each tuple would contain strings matching each regex group.
Now this is my problem: the regex on phoneRegex as far as i can tell contains only 6 groups (numbered on the code) (so i would expect tuples of length 6)
But when I print the tuples i get tuples of length 9
('800-420-7240', '800', '-', '420', '-', '7240', '', '', '')
('415-863-9900', '415', '-', '863', '-', '9900', '', '', '')
('415-863-9950', '415', '-', '863', '-', '9950', '', '', '')
What am i missing?
#! python3
# phoneAndEmail.py - Finds phone numbers and email addresses on the clipboard.
import pyperclip, re
phoneRegex = re.compile(r'''(
(\d{3}|\(\d{3}\))? # area code (first group?)0
(\s|-|\.)? # separator 1
(\d{3}) # first 3 digits 2
(\s|-|\.) # separator 3
(\d{4}) # last 4 digits 4
(\s*(ext|x|ext.)\s*(\d{2,5}))? # extension 5
)''', re.VERBOSE)
# Create email regex.
emailRegex = re.compile(r'''(
[a-zA-Z0-9._%+-]+ # username
# # # symbol
[a-zA-Z0-9.-]+ # domain name
(\.[a-zA-Z]{2,4}) # dot-something
)''', re.VERBOSE)
text = str(pyperclip.paste())
matches = []
for groups in phoneRegex.findall(text):
print(groups)
phoneNum = '-'.join([groups[1], groups[3], groups[5]])
if groups[8] != '':
phoneNum += ' x' + groups[8]
matches.append(phoneNum)
for groups in emailRegex.findall(text):
matches.append(groups[0])
# Copy results to the clipboard.
if len(matches) > 0:
pyperclip.copy('\n'.join(matches))
print('Copied to clipboard:')
print('\n'.join(matches))
else:
print('No phone numbers or email addresses found.')

Answer 1

Anything in parentheses will become a capturing group (and add one to the length of the re.findall tuple) unless you specify otherwise. To turn a sub-group into a non-capturing group, add ?: just inside the parentheses:
phoneRegex = re.compile(r'''(
(\d{3}|\(\d{3}\))?
(\s|-|\.)?
(\d{3})
(\s|-|\.)
(\d{4})
(\s*(?:ext|x|ext.)\s*(?:\d{2,5}))? # <---
)''', re.VERBOSE)
You can see the extension part was adding two additional capturing groups. With this updated version, you will have 7 items in your tuple. There are 7 instead of 6 because the entire string is matched as well.
The regex could be better, too. This is cleaner and will match more cases with the re.IGNORECASE flag:
phoneRegex = re.compile(r'''(
(\(?\d{3}\)?)
([\s.-])?
(\d{3})
([\s.-])
(\d{4})
\s* # don't need to capture whitespace
((?:ext\.?|x)\s*(?:\d{1,5}))?
)''', re.VERBOSE | re.IGNORECASE)