python - Running multiple threads at the same time

Question

So my goal is to have the do_something() function kickoff its own thread so that do_something() can run in parallel instead of having to wait for the previous one to finish. The problem is that it seems like it is not multithreading (meaning one thread finishes before the other one starts).

for i in range(len(array_of_letters)):

    if i == "a":
        t = threading.Thread(target=do_something())

        print "new thread started : %s"%(str(threading.current_thread().ident))     
        t.start()

I also have a current_thread().ident inside of the do_something() function but it seems like the identity of the thread that is started is the same as the main thread that the python script is running from. I think my approach is incorrect.

Answer 1

This is a common and easy to fall for mistake.

target=do_something() just executes your function at once in the main thread and passes None (the returning value of your function I suppose) as target function to the thread, which does not trigger any visible error; but does nothing either.

you have to pass the actual function not the result:

t = threading.Thread(target=do_something)

will work better