py 多进程，多线程

windows上运行

fork在windows无法运行

from multiprocessing import Process
import os

# 子进程要执行的代码
def run_proc(name):
    print('Run child process %s (%s)...' % (name, os.getpid()))

if __name__=='__main__':
    print('Parent process %s.' % os.getpid())
    # 创建子进程   
    p = Process(target=run_proc, args=('test',))
    print('Child process will start.')
    # 开始
    p.start()
    p.join()
    print('Child process end.')

异步与进程池

%2s意思是字符串长度为2，当原字符串的长度超过2时，按原长度打印，所以%2s的打印结果还是hello

from multiprocessing import Pool
import os, time, random

def long_time_task(name):
    print('Run task %s (%s)...' % (name, os.getpid()))
    start = time.time()
    time.sleep(random.random() * 3)
    end = time.time()
    print('Task %s runs %0.2f seconds.' % (name, (end - start)))

if __name__=='__main__':
    print('Parent process %s.' % os.getpid())
    p = Pool(6)
    for i in range(5):
        p.apply_async(long_time_task, args=(i,))
    print('Waiting for all subprocesses done...')
    p.close()
    p.join()
    print('All subprocesses done.')

#coding=utf-8
import multiprocessing

def do(n) :
  #获取当前线程的名字
  name = multiprocessing.current_process().name
  print (name,'starting')
  print ("worker ", n)
  return 

if __name__ == '__main__' :
    numList = []
    for i in range(5) :
        p = multiprocessing.Process(target=do, args=(i,))
        numList.append(p)
        p.start()
        p.join()
    print ("Process end.")