UUID and Unique Identifiers

Introduction

UUID (Universally Unique Identifier) provides unique identifiers for objects and distributed systems.

Creating UUIDs

import uuid

# Version 4 (random)
u1 = uuid.uuid4()
print(u1)  # e3b0c442-98fc-1c14-9af9-6e0f5e5d7b6c

# Version 1 (timestamp + MAC)
u2 = uuid.uuid1()

# From string
u3 = uuid.UUID("e3b0c442-98fc-1c14-9af9-6e0f5e5d7b6c")

# Check validity
print(uuid.UUID("invalid"))  # ValueError

Using UUIDs

import uuid

# As dictionary keys
users = {uuid.uuid4(): "Alice", uuid.uuid4(): "Bob"}

# For database primary keys
user_id = uuid.uuid4()
print(user_id.int)  # Integer representation

# Short representation
print(u1.hex[:8])  # Short unique ID

Practice Problems

1. Generate UUIDs for database records
2. Use UUID as cache keys
3. Create short unique identifiers
4. Validate UUID format
5. Generate version 1 UUIDs with custom node