python 线程池

1、新模块

from concurrent.futures import ThreadPoolExecutor
from concurrent.futures import ProcessPoolExecutor

2、方法

"""
线程数量一般是cpu个数*5
submit(函数名, 参数)
map(函数名, 可迭代对象)
obj.shutdown() 相当于obj.close()和obj.join()
obj.result()    获取返回值
and_done_callback(函数)，回调函数
done() 查看某个线程是否完成
"""

 

3、示例

import time
from concurrent.futures import ThreadPoolExecutor


def test1(n):
    time.sleep(0.5)
    print(n)
    return pow(n, 2)


t_pool = ThreadPoolExecutor(5)  # 线程池中线程的数量
t_li = []
for i in range(12):
    ret = t_pool.submit(test1, i) # 异步
    # print(ret.result())
    t_li.append(ret)
t_pool.shutdown()   # 相当于close()和join()方法
print('adaf')
for t in t_li: 
    print('***', t.result())

import time
from concurrent.futures import ThreadPoolExecutor


def test1(n):
    time.sleep(0.5)
    # print(n)
    return pow(n, 2)


def test2(m):
    print(m.result())


t_pool = ThreadPoolExecutor(5)  # 线程池中线程的数量
t_li = []
for i in range(12):
    t_pool.submit(test1, i).add_done_callback(test2)    # 回调函数

import time
from concurrent.futures import ThreadPoolExecutor


def test1(n):
    time.sleep(0.5)
    print(n)
    return pow(n, 2)


t_pool = ThreadPoolExecutor(5)  # 线程池中线程的数量
t_pool.map(test1, range(6))     # map(）异步