python - 优雅地编码尝试 : except chain

Question

我有一个concurrent.futures，通常与 chunksize=1 一起使用。但是，有时我会遇到需要更大块大小的大型数据集。目前我已经用以下代码解决了这个问题:

for i in datasets:
    try:
        with concurrent.futures.ProcessPoolExecutor() as executor:
            results=tuple(executor.map(do_something, parameters, chunksize=1)
    except concurrent.futures.process.BrokenProcessPool:
        try:
            with concurrent.futures.ProcessPoolExecutor() as executor:
                results=tuple(executor.map(do_something, parameters, chunksize=2)
        except concurrent.futures.process.BrokenProcessPool:
            try:
                with concurrent.futures.ProcessPoolExecutor() as executor:
                    results=tuple(executor.map(do_something, parameters, chunksize=4)
            etc. etc. etc....
            except concurrent.futures.process.BrokenProcessPool:
                   print('code failed')

这工作正常，但显然非常不优雅且丑陋。不管怎样，我可以更简单地做到这一点吗？

Answer 1

您可以使用 for 循环遍历 block 大小，如果成功则中断循环，或者输入 else block 输出错误信息:

for i in datasets:
    for chunksize in 1, 2, 4:
        try:
            with concurrent.futures.ProcessPoolExecutor() as executor:
                results=tuple(executor.map(do_something, parameters, chunksize=chunksize)
            break
        except concurrent.futures.process.BrokenProcessPool:
            pass
    else:
        print('code failed')