1. 一个多进程

# 引入多进程模块
import multiprocessing
# 引入时间模块
import time

# 放在子进程中执行的程序
def func(msg):
    for i in range(3):
        print(msg)
        time.sleep(1)

if __name__ == "__main__":
# 创建一个子进程 要传递的参数放在args中
    p = multiprocessing.Process(target=func, args=("hello", ))
    # 启动子进程
    p.start()
    # 主进程阻塞,等待子进程结束
    p.join()
    
    print("done")

2. 进程池

from multiprocessing import Pool

def func(msg):
    print(msg,'*** in func')
    time.sleep(3)

if __name__ == "__main__":
    # 创建进程池设置为5个进程
    pool = Pool(processes=5)
    for i in xrange(3):
        print i
        # 异步执行(相当于同时执行5个(并行),当然实例只添加了三个)
        pool.apply_async(func, ("hello %d" %(i), ))
        # 同步执行(一个一个的执行(串行))
        #pool.apply(func, ("hello %d" %(i), ))
    pool.close()
    #pool.terminate() #结束工作进程，不在处理未完成的任务
    pool.join() #主进程阻塞，等待子进程的退出， join方法要在close或terminate之后使用
    print("done")

3. 获取执行结果

from multiprocessing import Pool
import time

def func(msg):
    print("msg : ", msg)
    time.sleep(3)
    print "end"
    return "multi_result : " + msg

if __name__ == "__main__":
    pool = Pool(processes=4)
    # 定义result列表存储执行结果
    result = []
    for i in xrange(3):
        msg = "hello %d" %(i)
        multi_result = pool.apply_async(func, (msg, ))
        result.append(multi_result)
    pool.close()
    pool.join()
    for res in result:
    # 打印进程执行结果
        print(res.get())
    print("done")

4. 进程间内存共享

a.Array数组

#方法一，Array
from multiprocessing import Process,Array
temp = Array('i', [11,22,33,44])

def Foo(i):
    temp[i] = 100+i
    for item in temp:
        print(i,'----->',item)

for i in range(2):
    p = Process(target=Foo,args=(i,))
    p.start()  
'''
0 -----> 100
0 -----> 22
0 -----> 33
0 -----> 44
1 -----> 100
1 -----> 101
1 -----> 33
1 -----> 44
'''

b.Manager类

#方法二：manage.dict()共享数据
from multiprocessing import Process,Manager

manage = Manager()

dic = manage.dict()

def Foo(i):
    dic[i] = 100+i
    print(dic.values())

if __name__ == "__main__":
    for i in range(2):
        p = Process(target=Foo,args=(i,))
        p.start()
        p.join()

'''
[100]
[100, 101]
'''