UUID regular expressions (regex) with usage examples in Python

uuid_regex.py

import re

# RFC 4122 states that the characters should be output as lowercase, but
#   that input is case-insensitive. When validating input strings,
#   include re.I or re.IGNORECASE per below:

def _create_pattern(version):
    return re.compile(
        (
            '[a-f0-9]{8}-' +
            '[a-f0-9]{4}-' +
            version + '[a-f0-9]{3}-' +
            '[89ab][a-f0-9]{3}-' +
            '[a-f0-9]{12}$'
        ),
        re.IGNORECASE
    )


# -----------------------------------------------------------------------------
# Patterns
# -----------------------------------------------------------------------------

UUID_ALL_PATTERN = _create_pattern('[1-5]')
UUID_V4_PATTERN = _create_pattern('4')

# v1 with a randomized multicast MAC is a reasonable alternative to v4
# that is more optimal for DB indexing.
#
# UUID_V1_PATTERN = _create_pattern('1')
# UUID_V1_4_PATTERN = _create_pattern('[14]')


# -----------------------------------------------------------------------------
# Tests
# -----------------------------------------------------------------------------

assert UUID_ALL_PATTERN.match('18a3315c-5bd2-4009-bd35-71a054e8e097')
assert UUID_ALL_PATTERN.match('6df0d487-4541-11e6-b618-28cfe914732d')
assert UUID_ALL_PATTERN.match('6DF0D487-4541-11E6-B618-28CFE914732D')
assert not UUID_ALL_PATTERN.match('18a3315c-5bd2-4009-0d35-71a054e8e097')
assert not UUID_ALL_PATTERN.match('6df0d487-4541-01e6-b618-28cfe914732d')

assert UUID_V4_PATTERN.match('18a3315c-5bd2-4009-bd35-71a054e8e097')
assert not UUID_V4_PATTERN.match('6df0d487-4541-11e6-b618-28cfe914732d')
assert UUID_V4_INPUT_PATTERN.match('18A3315C-5BD2-4009-BD35-71A054E8E097')