Python脚本测试最新修改的文​​件-结果不一致 [英] Python script to test for most recently modified file - inconsistent results

问题描述

我发现了关于stackoverflow的帖子，这正是我想要集成到我正在编写的更大脚本中的内容：

I found this post on stackoverflow which was exactly what I wanted to integrate into a larger script I am writing: Find the newest folder in a directory in Python

我要检查最新文件或文件夹，因此修改了测试脚本，如下所示：

I want to check for the newest file or folder so modified the script for testing as follows:

#!/usr/bin/env python3.1

import os

def allFilesIn(b='.'):
    result = []
    for d in os.listdir(b):
        bd = os.path.join(b, d)
    result.append(bd)
    return result

latest_subdir = max(allFilesIn('/tmp/testforlatest'), key=os.path.getmtime)

print(latest_subdir)

但是我得到结果如下：

> touch /tmp/testforlatest/file1
> ls -t -1 /tmp/testforlatest/ | head -1
file1
> /tmp/testfornewestfile.py 
/tmp/testforlatest/file1
> touch /tmp/testforlatest/file2
> ls -t -1 /tmp/testforlatest/ | head -1
file2
> /tmp/testfornewestfile.py 
/tmp/testforlatest/file1
> mkdir /tmp/testforlatest/folder1
> ls -t -1 /tmp/testforlatest/ | head -1
folder1/
> /tmp/testfornewestfile.py 
/tmp/testforlatest/folder1
> mkdir /tmp/testforlatest/folder2
> ls -t -1 /tmp/testforlatest/ | head -1
folder2/
> /tmp/testfornewestfile.py 
/tmp/testforlatest/folder1
> touch /tmp/testforlatest/file3
> ls -t -1 /tmp/testforlatest/ | head -1
file3
> /tmp/testfornewestfile.py 
/tmp/testforlatest/folder1

有人会介意解释为什么

其他可能有用的信息：

> python3.1 --version
Python 3.1.3
> cat /etc/debian_version 
6.0.2

推荐答案

您的函数 allFilesIn 仅返回 os.listdir 返回的最后一个文件，因为您将结果附加到了for循环之外。您可能是这样想的：

Your function allFilesIn only returns the last file returned by os.listdir because you append the results outside of the for loop. You probably meant this:

def allFilesIn(b='.'):
    result = []
    for d in os.listdir(b):
        bd = os.path.join(b, d)
        result.append(bd)
    return result

顺便说一句，对于每个 PEP8 。您也可以很容易地将该函数压缩为列表理解：

As an aside it's preferable to use lowercase and underscores for function names per PEP8. You could also condense the function into a list comprehension pretty easily:

def all_files_in(path='.'):
    return [os.path.join(path, f) for f in os.listdir(path)]

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