进程池的用法

from concurrent.futures import ThreadPoolExecutor
import time
pool = ThreadPoolExecutor(50)

def f1():
    print(‘hello‘)
    time.sleep(1)


for i in range(200):
    pool.submit(f1)

    from concurrent.futures import ThreadPoolExecutor
import time
# import random
pool = ThreadPoolExecutor(50)

def f1(i):
    print(‘hello‘)
    time.sleep(1)
    i+=1
    return i

def f2(i):
    i=i.result()#接受到的i是一个对象，所以要result一下
    time.sleep(1)
    print(i)




for i in range(200):
    #此处的i是f1的参数，把f1的返回值用于f2的时候需要使用函数的回调
    pool.submit(f1,i).add_done_callback(f2)