如何创建文件和在Python中修改日期/时间? [英] How to get file creation & modification date/times in Python?

问题描述

我有一个脚本，需要根据文件创建和添加内容来做一些事情.修改日期，但必须在 Linux 上运行& Windows .

I have a script that needs to do some stuff based on file creation & modification dates but has to run on Linux & Windows.

什么是最好的跨平台方式来创建文件和在 Python 中修改date/times?

What's the best cross-platform way to get file creation & modification date/times in Python?

推荐答案

以跨平台的方式获取某种修改日期很容易-只需调用

Getting some sort of modification date in a cross-platform way is easy - just call os.path.getmtime(path) and you'll get the Unix timestamp of when the file at path was last modified.

获取文件创建的日期是不固定的且依赖于平台，甚至在三大操作系统之间也有所不同:

Getting file creation dates, on the other hand, is fiddly and platform-dependent, differing even between the three big OSes:

• 在 Windows 上，文件的ctime(记录在 os.path.getctime() 在Python中访问此文件，或者通话结果的 .st_ctime 属性到 os.stat() .该不会在Unix上起作用，其中ctime 是文件属性或的最后一次更改.
• 在 Mac 上以及其他一些基于Unix的操作系统上，您可以使用会创建存储创建日期(例如ext4将它们存储在st_crtime中)，Linux内核 Python来源.至少如果您使用的是ext4，数据 会附加到文件系统的inode中，但是没有方便的访问方法.

• On Windows, a file's ctime (documented at https://msdn.microsoft.com/en-us/library/14h5k7ff.aspx) stores its creation date. You can access this in Python through os.path.getctime() or the .st_ctime attribute of the result of a call to os.stat(). This won't work on Unix, where the ctime is the last time that the file's attributes or content were changed.
• On Mac, as well as some other Unix-based OSes, you can use the .st_birthtime attribute of the result of a call to os.stat().

• On Linux, this is currently impossible, at least without writing a C extension for Python. Although some file systems commonly used with Linux do store creation dates (for example, ext4 stores them in st_crtime) , the Linux kernel offers no way of accessing them; in particular, the structs it returns from stat() calls in C, as of the latest kernel version, don't contain any creation date fields. You can also see that the identifier st_crtime doesn't currently feature anywhere in the Python source. At least if you're on ext4, the data is attached to the inodes in the file system, but there's no convenient way of accessing it.

在Linux上，第二好的事情是通过mtime. rel ="noreferrer"> os.path.getmtime() 或 os.stat()结果的.st_mtime 属性.这将为您提供最后一次修改文件内容的时间，这对于某些用例可能就足够了.

The next-best thing on Linux is to access the file's mtime, through either os.path.getmtime() or the .st_mtime attribute of an os.stat() result. This will give you the last time the file's content was modified, which may be adequate for some use cases.

将所有这些放在一起，跨平台代码应该看起来像这样……

Putting this all together, cross-platform code should look something like this...

import os
import platform

def creation_date(path_to_file):
    """
    Try to get the date that a file was created, falling back to when it was
    last modified if that isn't possible.
    See http://stackoverflow.com/a/39501288/1709587 for explanation.
    """
    if platform.system() == 'Windows':
        return os.path.getctime(path_to_file)
    else:
        stat = os.stat(path_to_file)
        try:
            return stat.st_birthtime
        except AttributeError:
            # We're probably on Linux. No easy way to get creation dates here,
            # so we'll settle for when its content was last modified.
            return stat.st_mtime

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