Process

涉及模块：multiprocessing

---

• Process

  • p = Process()
  • p.start()
  • p.join()

from multiprocessing import Processimport 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())    p = Process(target=run_proc, args=('test',))    print('Child process will start.')    p.start()    p.join()    print('Child process end.')

• Pool

  • p=Pool(5)
  • p.apply_async(func,**args)
  • p.close()
  • p.join()

from multiprocessing import Poolimport os, time, randomdef 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(4)    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.')

Thread

涉及模块：threading

• Thread
  • t = threading.Thread(target=xxx,name=xxx,args=(xxx,xxx))
  • t.start()
  • t.join()
  • threading.curent_thread().name
  • l = threading.Lock()
  • l.acquire()
  • l.release()

import time, threading# 新线程执行的代码:def loop(s):    print(s)    print('thread %s is running...' % threading.current_thread().name)    n = 0    while n < 5:        n = n + 1        print('thread %s >>> %s' % (threading.current_thread().name, n))        time.sleep(1)    print('thread %s ended.' % threading.current_thread().name)print('thread %s is running...' % threading.current_thread().name)t = threading.Thread(target=loop, name='LoopThread', args=('a',))t.start()t.join()print('thread %s ended.' % threading.current_thread().name)

• ThreadLocal
  • 线程中共享所有的全局变量，需注意是否会死锁
  • 局部只有当前线程可以进行操作，但调用会很麻烦
  • local = threading.local()

import threading# 创建全局ThreadLocal对象:local_school = threading.local()def process_student():    # 获取当前线程关联的student:    std = local_school.student    print('Hello, %s (in %s)' % (std, threading.current_thread().name))def process_thread(name):    # 绑定ThreadLocal的student:    local_school.student = name    process_student()t1 = threading.Thread(target= process_thread, args=('Alice',), name='Thread-A')t2 = threading.Thread(target= process_thread, args=('Bob',), name='Thread-B')t1.start()t2.start()t1.join()t2.join()

第三方进程与线程模块

涉及模块：concurrent.futures

• ThreadPoolExecutor、ProcessPoolExecutor
  • submit
  • map
  • concurrent.futures.as_completed
• zip
  • 拼接
  • zip((1,2),(10,20)) ->((1,10),(2,20))

def sim_add(a):    return a[0]+a[1]    from concurrent.futures import ThreadPoolExecutorimport concurrent.futureswith ThreadPoolExecutor(max_workers=1) as t1:    future1 = t1.submit(sim_add,(1,2))    print(future1.result())print()var = [(1,2),(10,20),(100,200)]with ThreadPoolExecutor(max_workers=2) as t:    future = {t.submit(sim_add,tem): tem for tem in var}    for parameter,res in zip(var,concurrent.futures.as_completed(future)):        print("sim_add %s,return %s" % (parameter,res))    # 多次submit，不接收结果但是又想全部执行完    # concurrent.futures.wait()print()with ThreadPoolExecutor(max_workers=2) as t:    for f in t.map(sim_add,[(1,2),(2,3)]):        print(f)