Peter Hoffmann Code Blog

working with uuids on python

Python has a module to generate different UUIDs like defined in RFC 4122. uuids include creation time. This recipe extracts the timestamp information:

def get_posixtime(uuid1):
     """Convert the uuid1 timestamp to a standard posix timestamp
    """
    assert uuid1.version == 1, ValueError('only applies to type 1')
    t = uuid1.time
    t = t - 0x01b21dd213814000
    t = t / 1e7
    return t

Another task is to sort uuids by creation time. The default cmp function seems not to do this:

...  
    int = ((time_low << 96L) | (time_mid << 80L) |
               (time_hi_version << 64L) | (clock_seq << 48L) | node)
def __cmp__(self, other):
    if isinstance(other, UUID):
        return cmp(self.int, other.int)
    return NotImplemented

But since uuids have time attribute, a list with them can be sorted with

from operator import attrgetter
lst = [..]
lst.sort(key=attrgetter("time"))