Explain the concept of Green thread in the context of Python and tell about its differences from regular threads.

Green thread — is a thread managed by a virtual machine or runtime, not by the operating system. In Python, the concept of green threads is implemented through libraries such as gevent or eventlet.

Differences from regular OS threads:

• Green threads run in a single system thread, and switching between them occurs at the application level.
• They are lighter and faster to create and switch, as they do not require OS context switching.
• They do not utilize multiprocessing, as they operate within a single core.
• They are not affected by GIL (Global Interpreter Lock) issues in Python, as switching is manually managed.

Example of using green threads with gevent:

import gevent

def task(name):
    print(f"Task {name} started")
    gevent.sleep(1)
    print(f"Task {name} completed")

g1 = gevent.spawn(task, 'A')
 g2 = gevent.spawn(task, 'B')

g1.join()
 g2.join()

Thus, green threads are suitable for I/O-bound tasks where high concurrency without OS overhead is important.