import re
regex = re.compile(r"\bankit_bill_20[0-9][0-9]-(?:[1-9]|1[0-2]|0[0-9])-(?:[1-9]|1[0-9]|2[0-9]|3[0-1]|0[0-9])-[0-9]{2}_(?:abc|cde)[0-6]{0,2}\.csv\b", flags=re.MULTILINE)
test_str = ("ankit_bill_2019-12-02-00_abc01.csv\n"
"ankit_bill_2019-12-02-00_abc.csv\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