- 多进程学习
- 注意逗号
- 注意使用进程池
- 注意使用异步
- 注意查看任务管理器，多进程是否跑起来
import multiprocessing
import time
'''
进程池、线程池的使用有四种方式：apply_async、apply、map_async、map。其中apply_async和map_async是异步的，也就是启动进程函数之后会继续执行
后续的代码不用等待进程函数返回。apply_async和map_async方式提供了一写获取进程函数状态的函数：ready()、successful()、get()。
'''
def func(msg):
print('msg: ', msg)
time.sleep(1)
print('********')
return 'func_return: %s' % msg
if __name__ == '__main__':
'''
# apply_async
print('\n--------apply_async------------')
pool = multiprocessing.Pool(processes=4)
results = []
for i in range(10):
msg = 'hello world %d' % i
result = pool.apply_async(func, (msg,))
results.append(result)
print('apply_async: 不堵塞')
for i in results:
i.wait() # 等待进程函数执行完毕
for i in results:
if i.ready(): # 进程函数是否已经启动了
if i.successful(): # 进程函数是否执行成功
print(i.get()) # 进程函数返回值
'''
'''
# apply
print('\n--------apply------------')
pool = multiprocessing.Pool(processes=4)
results = []
for i in range(10):
msg = 'hello world %d' % i
result = pool.apply(func, (msg,))
results.append(result)
print('apply: 阻塞') # 执行完func才执行该句
pool.close()
pool.join() # join语句要放在close之后
print(results)
'''
'''
# map
print('\n--------map------------')
args = [1, 2, 4, 5, 7, 8]
pool = multiprocessing.Pool(processes=6)
return_data = pool.map(func, args)
print('阻塞') # 执行完func才执行该句
pool.close()
pool.join() # join语句要放在close之后
print(return_data)
'''
# map_async
print('\n--------map_async------------')
pool = multiprocessing.Pool(processes=6)
args = [1, 2, 4, 5, 7, 8]
result = pool.map_async(func, args)
print('ready: ', result.ready())
print('不堵塞')
result.wait() # 等待所有进程函数执行完毕
if result.ready(): # 进程函数是否已经启动了
if result.successful(): # 进程函数是否执行成功
print(result.get()) # 进程函数返回值
