Execute 'N' functions in parallel in python

Question

I know this question has been asked multiple times but I couldn't find an answer which would help me. My question is can we execute two functions in parallel in python where each function has a for loop running and printing some values. For example, I have two functions a() and b() where a() is printing the numbers 1..n (say n=3) and b() is printing the numbers 11..n(say n=13) along with the current time. I expect the output to be like :

function a :1 2018-11-02 15:32:58
function b :11 2018-11-02 15:32:58
function a :2 2018-11-02 15:32:59
function b :12 2018-11-02 15:32:59

but it currently prints the following :

function a :1 2018-11-02 15:32:58
function a :2 2018-11-02 15:32:59
function b :11 2018-11-02 15:33:00
function b :12 2018-11-02 15:33:01

Code:

import time
from threading import Thread
import datetime
def a():
    for i in range(1,3):
        print 'function a :'+str(i) + ' ' + str(datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S"))
        time.sleep(1)
def b():
    for i in range(11,13):
        print 'function b :'+str(i) + ' ' + str(datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S"))
        time.sleep(1)

if __name__=="__main__":
    t1=Thread(target=a())
    t2=Thread(target=b())
    t1.start()
    t2.start()

Rob Bricheno · Accepted Answer · 2018-11-02 16:04:22Z

1

The problem here is that you have the target as a() rather than a (note the parentheses). What that means is, you are calling the function a and then passing the result of that as the target to Thread. That isn't what you wanted - you want the target to be the function a itself. So just remove the parentheses when instantiating your Threads like so:

if __name__=="__main__":
    t1=Thread(target=a)
    t2=Thread(target=b)
    t1.start()
    t2.start()

answered Nov 2, 2018 at 16:04

Rob Bricheno

4,66317 silver badges30 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Execute 'N' functions in parallel in python

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related