How to check UUID validity in Python?

Question

I have a string that should be a UUID. Is there any built-in Python function available to check whether the UUID is valid or not, and to check its version?

Answer 1

I found this question while I was looking for a Python answer. To help people in the same situation, I've added the Python solution.

You can use the uuid module:

#!/usr/bin/env python

from uuid import UUID

def is_valid_uuid(uuid_to_test, version=4):
    """
    Check if uuid_to_test is a valid UUID.
    
     Parameters
    ----------
    uuid_to_test : str
    version : {1, 2, 3, 4}
    
     Returns
    -------
    `True` if uuid_to_test is a valid UUID, otherwise `False`.
    
     Examples
    --------
    >>> is_valid_uuid('c9bf9e57-1685-4c89-bafb-ff5af830be8a')
    True
    >>> is_valid_uuid('c9bf9e58')
    False
    """
    
    try:
        uuid_obj = UUID(uuid_to_test, version=version)
    except ValueError:
        return False
    return str(uuid_obj) == uuid_to_test


if __name__ == '__main__':
    import doctest
    doctest.testmod()

Answer 2

All the existing answers use regex. If you're using Python, you might want to consider a try/except in case you don't want to use regex: (Bit shorter than the answer above).

Our validator would then be:

import uuid

def is_valid_uuid(val):
    try:
        uuid.UUID(str(val))
        return True
    except ValueError:
        return False

>>> is_valid_uuid(1)
False
>>> is_valid_uuid("123-UUID-wannabe")
False
>>> is_valid_uuid({"A":"b"})
False
>>> is_valid_uuid([1, 2, 3])
False
>>> is_valid_uuid(uuid.uuid4())
True
>>> is_valid_uuid(str(uuid.uuid4()))
True
>>> is_valid_uuid(uuid.uuid4().hex)
True
>>> is_valid_uuid(uuid.uuid3(uuid.NAMESPACE_DNS, 'example.net'))
True
>>> is_valid_uuid(uuid.uuid5(uuid.NAMESPACE_DNS, 'example.net'))
True
>>> is_valid_uuid("{20f5484b-88ae-49b0-8af0-3a389b4917dd}")
True
>>> is_valid_uuid("20f5484b88ae49b08af03a389b4917dd")
True

Answer 3

To check the validity of a UUID string, simply try to create a new uuid object with it. If it's invalid...

uuid.UUID("foo")
# => ValueError: badly formed hexadecimal UUID string

If you need to know the version of the UUID, it's right there in the UUID API:

uuid.UUID('302a4299-736e-4ef3-84fc-a9f400e84b24').version
# => 4

Answer 4

import re

UUID_PATTERN = re.compile(r'^[\da-f]{8}-([\da-f]{4}-){3}[\da-f]{12}$', re.IGNORECASE)
uuid = '20f5484b-88ae-49b0-8af0-3a389b4917dd'

return bool(UUID_PATTERN.match(uuid))