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I am getting an error when I run my code: "threads can only be started once"

it has to do with my for I in range(10)

I kill the threads right after I start it so in theory all threads should be killed before going back into the next loop to create another set of threads.

What I am trying to do is to get the time it takes to run a thread

def __startThreads__(self):
        print("How Many =", self.howMany)
        start1 = time()
        for i in range(10):
            start2 = time()
            for i in range(self.howMany):
                self.threads.append( ThreadEntity( str(i), iAmTheProgramCode ) )
            for each in self.threads: 
                each.start()
            for each in self.threads:
                each.killThreadEntity()
            stop2 = time()
            threadtime = stop2 - start2
            print(threadtime)
        stop1 = time()
        threadTotalTime = stop1 - start1
        print(threadTotalTime)
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Next time, please format your code appropriately ;-) I fixed that for you, basically it was missing an indent. –  Uli Köhler Jan 28 at 23:52
    
How do you know it has to do with the line: 'for I in range(10)'? –  BakaKuna Jan 29 at 0:00
    
if I put for I in range(1) it doesn't have a problem because it only tries 1 iteration of the loop but when I increase it to 2 it crashes –  John Jan 29 at 0:02
    
Here is the error I get: –  John Jan 29 at 0:04
    
Exception in Tkinter callback Traceback (most recent call last): File "C:\Python33\lib\tkinter_init_.py", line 1475, in call return self.func(*args) File "C:\Users\cslaptop\Desktop\SimpleVirtualShell.py", line 133, in startThreads each.start() File "C:\Python33\lib\threading.py", line 836, in start raise RuntimeError("threads can only be started once") RuntimeError: threads can only be started once –  John Jan 29 at 0:05

1 Answer 1

up vote 1 down vote accepted

you can't start a thread after you killed it.

you iterate over self.threads 10 times (for i in range(10)). and in each iteration you start all the threads in it (and append some new ones but you also iterate over the previous which were killed).

I think that what you ment to do is to empty the threads list before each iteration.

try add the next line after for i in range(10):

self.threads = []
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