Why this string matches the regular expression?

Question

Why this string matches the pattern ?

  pattern = """
    ^Page \d of \d$|
    ^Group \d Notes$|
    ^More word lists and tips at http://wwwmajortests.com/word-lists$|
    """
    re.match(pattern, "stackoverflow", re.VERBOSE)

According to me it should match strings like "Page 1 of 1" or "Group 1 Notes".

Answer 1

In your regular expression, there's trailing |:

# ^More word lists and tips at http://wwwmajortests.com/word-lists$|
#                                                                  ^

Empty pattern matches any string:

>>> import re
>>> re.match('abc|', 'abc')
<_sre.SRE_Match object at 0x7fc63f3ff3d8>
>>> re.match('abc|', 'bbbb')
<_sre.SRE_Match object at 0x7fc63f3ff440>

So, Remove the trailing |.

BTW, you don't need ^ becasue re.match checks for a match only at the beginning of the string.

And, I recommend you to use raw strings(r'....') to correctly escape backslahes.

---

ADDITIONAL NOTE

\d matches only a single digit. Use \d+ if you also want to match multiple digits.