Scriptling Scriptling

uuid

The uuid library generates universally unique identifiers (UUIDs) using time-based, random, name-based or sortable timestamp-based schemes. Each function returns a UUID object; str(u) gives the canonical form such as "550e8400-e29b-41d4-a716-446655440000".

Available Functions

Function Description
uuid1() Version 1 UUID from the current time and MAC address.
uuid4() Version 4 (random) UUID; the usual general-purpose choice.
uuid3(namespace, name) Version 3 (MD5, name-based) UUID; the same inputs always give the same UUID.
uuid5(namespace, name) Version 5 (SHA-1, name-based) UUID; the same inputs always give the same UUID.
uuid7() Version 7 UUID from a millisecond timestamp; sorts in creation order, which suits database keys.
UUID(string) Parse a UUID from its hyphenated, bare-hex or URN string form.

The namespace constants NAMESPACE_DNS, NAMESPACE_URL, NAMESPACE_OID and NAMESPACE_X500 are UUID objects that can be passed to uuid3()/uuid5().

UUID Objects

A UUID supports str(), repr(), ==/!=, ordering (<, <=, >, >=) and hashing, so it works as a dict key, set member and sorted() item. Attributes: hex (32 hex digits), version, variant, bytes (16 bytes) and urn.

UUID Versions Comparison

Version Based On Sortable Use Case
uuid1() Time + MAC Partially Legacy systems, audit trails
uuid4() Random No General purpose, most common
uuid7() Timestamp Yes Database keys, distributed systems

Example

import uuid

request_id = uuid.uuid4()
print(str(request_id), len(str(request_id)))   # 550e8400-... 36
print(request_id.version, request_id.hex[:8])  # 4 ...

a = uuid.uuid7()                  # time-ordered: later IDs sort after earlier ones
b = uuid.uuid7()
print(a < b, a.version)           # True 7

# Name-based UUIDs are deterministic
print(uuid.uuid5(uuid.NAMESPACE_DNS, "example.com"))
# cfbff0d1-9375-5685-968c-48ce8b15ae17

seen = {request_id: "first"}      # hashable
print(uuid.UUID(str(request_id)) == request_id)   # True

Differences from Python

  • .int is not available: a UUID is a 128-bit integer and scriptling integers are 64-bit.
  • uuid.UUID(s) takes one positional string (hyphenated, bare hex or urn:uuid: form), not the hex=, bytes=, int= or fields= keywords; .fields, .time and the other less common attributes are not provided.
  • uuid7() matches Python 3.14+.

See Also

  • random: random number generation.
  • hashlib: cryptographic hash functions.