How can I use semaphores in Python?

How can I use semaphores in Python?

You can use the threading module in Python, which provides a Semaphore class to manage access to shared resources.

Can you give me an example of how to implement a semaphore?

Sure! Here's a simple example:

import threading
import time

semaphore = threading.Semaphore(2)  # Allow 2 threads to access the resource

def access_resource(thread_id):
    with semaphore:
        print(f'Thread {thread_id} is accessing the resource.')
        time.sleep(2)  # Simulate resource access
        print(f'Thread {thread_id} is done.')

threads = []
for i in range(5):
    t = threading.Thread(target=access_resource, args=(i,))
    threads.append(t)
    t.start()

for t in threads:
    t.join()

What happens if more than two threads try to access the resource?

If more than two threads try to access the resource, they will be blocked until one of the threads currently holding the semaphore releases it.

Are there any other synchronization primitives in Python?

Yes, Python also provides other synchronization primitives like Lock, Event, and Condition in the threading module.