import re
regex = re.compile(r"""
(?=
[ ]{0,8}? \d{1,9}
( .* ) $ # (1)
)
[ \d]{9}
(?= \1 $ )
""", flags=re.VERBOSE | re.MULTILINE)
test_str = ("examples of valid strings\n\n"
"123456789\n"
"kfasdf 3456789asdf\n"
"a 1\n\n"
"and examples of invalid strings\n\n"
"12345 789\n"
"1 9\n"
"a 678a\n")
matches = regex.finditer(test_str)
for match_num, match in enumerate(matches, start=1):
print(f"Match {match_num} was found at {match.start()}-{match.end()}: {match.group()}")
for group_num, group in enumerate(match.groups(), start=1):
print(f"Group {group_num} found at {match.start(group_num)}-{match.end(group_num)}: {group}")
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Python, please visit: https://docs.python.org/3/library/re.html