What does the join() method do in Python threading?

The join() method in Python threading is used to wait for a thread to complete its execution before continuing with the rest of the program. When join() is called on a thread, the main program pauses until the thread has finished running.

import threading
import time

def slow_function():
    time.sleep(2)
    print("Thread completed")

# Creating and starting a thread
thread = threading.Thread(target=slow_function)
thread.start()

# Waiting for the thread to finish
thread.join()

print("Main program continues")

In this example, the main program waits for the thread to finish executing the slow_function before printing “Main program continues”.

The join() method is essential for synchronizing threads, ensuring that certain tasks are completed before moving on to the next steps in your program.