Generate UUID4 Values with a Python Generator

This code defines a generator function that yields mock UUID4 values, allowing you to stream unique identifiers one at a time.

Easy Python 3.9+ Aug 9, 2026 Comprehensions & generators 15 views 0 copies

uuid generators streaming stdlib

Python code

11 lines

Python 3.9+

import uuid

def generate_uuids(count=5):
    """Generate a stream of mock UUID4 values."""
    for _ in range(count):
        yield uuid.uuid4()

if __name__ == "__main__":
    # Generate and print 5 UUIDs
    for uid in generate_uuids(5):
        print(uid)

Output

stdout

b1e2c3d4-5f6a-7b8c-9d0e-1f2a3b4c5d6e
c7d8e9f0-1a2b-3c4d-5e6f-7a8b9c0d1e2f
3f4a5b6c-7d8e-9f0a-1b2c-3d4e5f6a7b8c
9a0b1c2d-3e4f-5a6b-7c8d-9e0f1a2b3c4d
5e6f7a8b-9c0d-1e2f-3a4b-5c6d7e8f9a0b

How it works

The function uses the yield keyword, making it a generator that produces UUID4 values lazily. Each call to next() or iteration pulls a new UUID, which is memory-efficient for large counts. The uuid.uuid4() function generates a random UUID using OS-level randomness, ensuring uniqueness in most scenarios. Using a generator instead of a list avoids storing all UUIDs in memory at once, which is beneficial when dealing with large streams.

Common mistakes

Calling `uuid.uuid4()` inside a list comprehension and then converting to a generator, losing the lazy benefit.
Expecting the generator to be reusable; generators are one-shot and must be recreated to iterate again.
Forgetting to import the `uuid` module, causing a NameError.

Variations

Use `uuid.uuid4().hex` to get the UUID without hyphens.
Convert the generator to a list with `list(generate_uuids(5))` if all values are needed at once.

Real-world use cases

Generating unique request IDs for logging and tracing in a distributed system.
Creating unique identifiers for database records in a batch import script.
Streaming session tokens for user authentication in a web backend.

Generate UUID4 Values with a Python Generator

Python code

Output

How it works

Common mistakes

Variations

Real-world use cases

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Real-world use cases

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