Simple multithread for loop in Python

Question

I searched everywhere and I don't find any simple example of iterating a loop with multithreading.

For example, how can I multithread this loop?

for item in range(0, 1000):
    print(item)

Is there any way to cut it in like 4 threads, so each thread has 250 iterations?

Answer 1

Easiest way is with multiprocessing.dummy (which uses threads instead of processes) and a Pool

import multiprocessing.dummy as mp 

def do_print(s):
    print s

if __name__=="__main__":
    p=mp.Pool(4)
    p.map(do_print,range(0,10)) # range(0,1000) if you want to replicate your example
    p.close()
    p.join()

Maybe you want to try real multiprocessing, too if you want to better utilize multiple CPUs but there are several caveats and guidelines to follow then.

Possibly other methods of Pool would better suit your needs - depending on what you are actually trying to do.