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Python concurrent包是Python标准库中的一个模块，提供了多线程、多进程和协程等并发编程方式的支持。具体来说，该包提供了一些实用工具，使开发者可以更方便地编写并发程序。以下是一些使用Python concurrent包的示例：

1. 多线程

python
import threading

def worker(num):
"""Thread worker function"""
print(f"Worker {num} starting")
# do some work here...
print(f"Worker {num} finished")

# Create 5 threads
threads = []
for i in range(5):
t = threading.Thread(target=worker, args=(i,))
threads.append(t)

# Start all threads
for t in threads:
t.start()

# Wait for all threads to complete
for t in threads:
t.join()


上面的代码创建了5个线程，并且每个线程都执行 worker 函数。最后通过调用 join 方法来等待所有线程的执行完成。

2. 多进程

python
import multiprocessing

def worker(num):
"""Process worker function"""
print(f"Worker {num} starting")
# do some work here...
print(f"Worker {num} finished")

# Create 5 processes
processes = []
for i in range(5):
p = multiprocessing.Process(target=worker, args=(i,))
processes.append(p)

# Start all processes
for p in processes:
p.start()

# Wait for all processes to complete
for p in processes:
p.join()


与多线程类似，上面的代码创建了5个进程，并且每个进程都执行 worker 函数。最后通过调用 join 方法来等待所有进程的执行完成。

3. 协程

python
import asyncio

async def worker(num):
"""Coroutine worker function"""
print(f"Worker {num} starting")
# do some work here...
await asyncio.sleep(0.1)
print(f"Worker {num} finished")

# Create event loop and tasks
async def main():
tasks = [asyncio.create_task(worker(i)) for i in range(5)]
await asyncio.gather(*tasks)

# Run event loop
if __name__ == "__main__":
asyncio.run(main())


上面的代码创建了5个协程，并且每个协程都执行 worker 函数。最后通过调用 asyncio.gather 方法来等待所有协程的执行完成。注意，在Python中使用协程需要在异步上下文中（例如，使用 asyncio 模块）执行它们。