Python 2.7: How to compensate for missing pool.starmap?

Question

I have defined this function

def writeonfiles(a,seed):
    random.seed(seed)

    f = open(a, \"w+\")
    for i in range(0,10):
        j = random.randint(0,         


        

Answer 1

Python 2.7 lacks the starmap pool-method from Python 3.3+ . You can overcome this by decorating your target function with a wrapper, which unpacks the argument-tuple and calls the target function:

import os
from multiprocessing import Pool
import random
from functools import wraps


def unpack(func):
    @wraps(func)
    def wrapper(arg_tuple):
        return func(*arg_tuple)
    return wrapper

@unpack
def write_on_files(a, seed):
    random.seed(seed)
    print("%d opening file %s" % (os.getpid(), a))  # simulate
    for _ in range(10):
        j = random.randint(0, 10)
       print("%d writing %d to file %s" % (os.getpid(), j, a))  # simulate


if __name__ == '__main__':

    folder = ["Test/%d.csv" % i for i in range(0, 4)]
    seed = [234124, 663123, 12345, 123833]

    arguments = zip(folder, seed)

    pool = Pool(4)
    pool.map(write_on_files, iterable=arguments)
    pool.close()
    pool.join()