如何创建一个while循环来检查文件是否存在? [英] How to create a while loop to check if a file exists?

问题描述

我要做的是检查文件是否存在，如果不存在，请执行一个操作，然后再次检查，直到文件存在，然后代码继续执行其他操作.

What I want to do is to check if a file exists, and if it doesn't, perform an action, then check again, until the file exists and then the code continues on with other operations.

推荐答案

为简单起见，我将实现一个小的轮询功能，并为安全起见设置超时:

For simplicity, I would implement a small polling function, with a timeout for safety:

def open_file(path_to_file, attempts=0, timeout=5, sleep_int=5):
    if attempts < timeout and os.path.exists(path_to_file) and os.path.isfile(path_to_file): 
        try:
            file = open(path_to_file)
            return file
        except:
            # perform an action
            sleep(sleep_int)
            open_file(path_to_file, attempts + 1)

我还将研究使用Python内置的轮询，因为这将跟踪/报告文件描述符的I/O事件

I would also look into using Python built-in polling, as this will track/report I/O events for your file descriptor

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