Threading in Python

By import threading :

acc. to Python Docs:
Threads can be created by passing a callable object to the constructor, or by overriding the run() method in a subclass.

1) overriding the run() method in a subclass

import threading
import time

class myThreading(threading.Thread):
    def __init__(self,counter):
        print "In init__"
        self.counter=counter
        threading.Thread.__init__(self)
   
    def run(self):
        print "in Run " + self.name
        tFunc(self.name,self.counter)
        #time.sleep(1)
   
    def pCount(self):
        print threading.activeCount()
        #print threading.enumerate()
       
def tFunc(name,counter):
    while counter :
        print "Name:" + name
        counter -= 1
       
tObj1=myThreading(2)
tObj1.start()


start() starts the thread activity. It arranges for the object’s run() method to be invoked in a separate thread of control.

start() will create a thread. run() function will be executed in tht thread
tObj1.run() will not create thread. It will simply execute run method of same class.
Or in other words tObj1.run() will just call run() function  in the current (calling) Thread.

2) passing a callable object to the constructor

import threading
import time

class myThreading(threading.Thread):
    def __init__(self):
        threading.Thread.__init__(self,target=tFunc,name='tName',args=(2,))

def tFunc(counter):
    while counter:
        print "Count :", counter
        counter -= 1
       
tObj1=myThreading()
tObj1.start()