python - multithreading — join() method

Question

import threading, time

class test(threading.Thread):                 

    def __init__(self,name,delay):
        threading.Thread.__init__(self)
        self.name = name
        self.delay = delay

    def run(self):
        c = 0
        while True:
            time.sleep(self.delay)            
            print 'This is thread %s on line %s' %(self.name,c)
            c = c + 1 
            if c == 15:
                print 'End of thread %s' % self.name
                break

one = test('one', 1).start()
two = test('two', 3).start()

one.join()
two.join()

print 'End of main'

Problem: cannot get join() methods to work properly, gives the following error:

Traceback (most recent call last)line 29, in <module> join() NameError: name 'join' is not defined

if i remove:

one.join
two.join

the code works perfectly fine.

I wanted to print the last line,

print 'End of main'

after the two threads have ended. I can't seem to understand why join() is not an attribute of the two instances?

Answer 1

one = test('one', 1).start()
two = test('two', 3).start()

Your problem is that start() doesn't do a return self . one and two are not threads. They're None or whatever the return value of start() actually is.

This works:

one = test('one', 1)
one.start()
two = test('two', 3)
two.start()