Python class 作为线程，不打印输入

Question

I'm running Python 3 and are trying to create my own class for threads :

class myThread(multiprocessing.Process):
  def __init__(self, i):
    multiprocessing.Process.__init__(self)
    self.i = i
  def run(self):
    while True:
      print(self.i)

When creating the thread, it doesn't output i :

multiprocessing.Process(target=myThread, args=[5]).start()

Answer 1

You have to create instances from the class that inherits from threading.Thread and use the start method in order to start the block in the def run() block:

import threading

class myThread(threading.Thread):
  def __init__(self, i):
    threading.Thread.__init__(self)
    self.i = i
  def run(self):
    while True:
      print(self.i)



for num in range(5): # number of threads to create
    _definition = myThread(i = 'myoutput')
    _definition.start()

Answer 2

The issue is that this only creates a thread in the process. It doesn't start that thread.

multiprocessing.Process(target=myThread, args=[5])

You could do the following but the combination of a Thread and a Process in this manner is somewhat redundant as one could have used the main Thread of the Process instead.

import threading
import multiprocessing

class myThread(threading.Thread):
  def __init__(self, i):
    threading.Thread.__init__(self)
    self.i = i
  def run(self):
    while True:
      print(self.i)

def wrapper(i):
    t = myThread(i)
    t.start()
    t.join()

if __name__=="__main__":
    p = multiprocessing.Process(target=wrapper, args=[5])
    p.start()
    p.join()

The following does the same but without the Thread:

import multiprocessing

def my_target(i):
    while True:
        print(self.i)

if __name__=="__main__":
    p = multiprocessing.Process(target=my_target, args=[5])
    p.start()
    p.join()