Simple implementation code of process pool in python

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Go back to python and use the python process pool.

I remember during the previous interview, the interviewer asked: Do you know the default parameters of the process pool? I didn't answer, but later I found out that there are default parameters. Let’s take a look at its default parameters

1. Without parameters

from multiprocessing.pool import Pool
from time import sleep
def fun(a):
    sleep(5)
    print(a)

if __name__ == '__main__':
    p = Pool()      # 这里不加参数，但是进程池的默认大小，等于电脑CPU的核数
                    # 也是创建子进程的个数，也是每次打印的数字的个数
    for i in range(10):
        p.apply_async(fun, args= (i, ))
    p.close()
    p.join()        # 等待所有子进程结束，再往后执行
    print("end")

2. With parameters5

from multiprocessing.pool import Pool
from time import sleep
def fun(a):
    sleep(5)
    print(a)
if __name__ == '__main__':
    p = Pool(5)     # 最多执行5个进程，打印5个数
    for i in range(10):
        p.apply_async(fun, args= (i, ))
    p.close()
    p.join()        # 等待所有子进程结束，再往后执行
    print("end")

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