How to communicate between threads in Python?

In Python, multiple threads can communicate with each other in the following ways:

1. Shared variable: Multiple threads can share the same variable to communicate through reading and writing. It is important to note that multiple threads accessing a shared variable can lead to issues like Race Condition, so it is necessary to use locking mechanisms to ensure mutual exclusion in accessing the shared variable.
2. Queue: A queue can be used to facilitate communication between threads. One thread can put data into the queue, and another thread can retrieve data from the queue. Python provides a thread-safe queue module named “queue”.
3. Pipe: Threads can communicate with each other using a pipe. One thread can write data to one end of the pipe, while another thread can read data from the other end. In Python, the multiprocessing.Pipe module is provided for this purpose.
4. Events can be used in Python to achieve communication between threads. One thread can notify other threads by setting the state of an event, while other threads can wait for the event’s state to change. Python provides the threading.Event object for this purpose.
5. Condition variable: Condition variables can be used to facilitate communication between threads. One thread can notify other threads by changing the state of the condition variable, while other threads can wait for the condition variable to change. In Python, the threading.Condition object provides this functionality.
6. Semaphore: You can use a semaphore to control concurrent access between multiple threads. A thread can execute critical section code by acquiring the semaphore permit, while other threads need to wait for the semaphore permit. Python provides a semaphore object in threading.Semaphore.

It is important to avoid situations of deadlock and livelock when communicating using multiple threads, so it is necessary to carefully design the collaboration between the threads.