What are atomic operations in Python and can you give me examples?

What are atomic operations in Python and can you give me examples?

Atomic operations are operations that are completed in a single step without the possibility of interruption. In Python, examples include operations on built-in types like integers and strings, as well as using the threading module for thread-safe operations.

Can you show me a code example of an atomic operation?

Sure! Here's a simple example using the threading module to safely increment a counter:

import threading

counter = 0
lock = threading.Lock()

def increment():
    global counter
    with lock:
        counter += 1

threads = [threading.Thread(target=increment) for _ in range(100)]
for thread in threads:
    thread.start()
for thread in threads:
    thread.join()

print(counter)  # Should print 100

What happens if I don't use a lock in this example?

If you don't use a lock, multiple threads may read and write to the counter variable simultaneously, leading to a race condition. This can result in an incorrect final value, as some increments may be lost.

Are there atomic operations in Python that don't require locks?

Yes, certain operations on built-in types like integers and strings are atomic in Python. For example, incrementing an integer is atomic, but you should still be cautious when using it in a multi-threaded context.