Python multi threading vs multi processing

A very good article on python multi threading vs multi processing

Access shared resource

Sometime we need to access shared document, for example when our application write to a single file on multi-thread. In this case we need to access the through locking.

This technique is useful for web crawler.

lock=threading.Lock()
def writeToFile():
    lock.acquire()
    try:
        //write data
    finally:
        lock.release()

Python Threading Use A Thread Class

 '''
    This code use a thread class
    - Save this class named 'AnyName.py'
 - Run this code you need class 'ThreadClass.py'
'''
import ThreadClass

for i in range(1,4):
    threadObject=ThreadClass.ThreadClass(i)
    threadObject.start()

Output:

output:  output: 1output:  
 23

output:  1
output:  2output: 
 3
output:  1
output: output:   32

Python Threading

'''
    This code use python threading syntax
    - Save this class named 'ThreadClass.py'
'''
import threading
import time

class ThreadClass(threading.Thread):
    def __init__(self,data):
        threading.Thread.__init__(self)
        self.data=data
        
    def run(self):
        for i in range(0,3):
            print "output: ",self.data
            time.sleep(1);