Inherit thread class in python

Question

I have some questions about inheriting thread class.

class MyThread(threading.Thread):
  def __init__(self, num):
    threading.Thread.__init__(self)
    self.num = num

  def run(self):
    print("Thread", self.num)
    time.sleep(1)

why can't I only override the run method? The Python document of threading mention that "The Thread class represents an activity that is run in a separate thread of control. There are two ways to specify the activity: by passing a callable object to the constructor, or by overriding the run() method in a subclass."

Why does the above example code override the constructor also?

Answer 1

The constructor is overridden to pass the num parameter from the place where instance of MyThread is created to the run method.

Note that you do not call run method directly so you can't pass any parameters to it unless you store them in constructor.

If you don't need to pass parameters you can override only run method.