为什么ProcessPoolExecutor连续工作？

Question

from concurrent.futures import ProcessPoolExecutor
import os
import time

def parInnerLoop(item):
    print(f'Processing {os.getpid()} started on {item}')
    time.sleep(3)
    print(f'Processing {os.getpid()} done on {item}')

def main():
    executor = ProcessPoolExecutor(max_workers=4)

    for itemNo in range(10):
        executor.submit(parInnerLoop(itemNo))

if __name__ == '__main__':
    main()

我想实现的是并行for循环，类似于MatLab，例如：

parfor itemNo = 0:9
    parInnerLoop(itemNo);
end

我得到的是：所有os.getpid都相同，并且执行顺序发生。有帮助吗？

Windows，VSCodium / VSCode，Python 3.7.3

Answer 1

如@Klaus所述，需要从executor.submit(parInnerLoop(itemNo))更改为executor.submit(parInnerLoop, itemNo)。