Python 3.7下使用Regex提取指定路径中.sav文件名的求助

Hey there! Let's break down why your current regex isn't working and get you the right filename easily.

What's Wrong With Your Current Regex? #

Your pattern r'\\(.+).sav' uses greedy matching with .+, which means it will grab everything starting from the first backslash (\) in your path all the way up to the last .sav — that's why you're getting a huge chunk instead of just the final filename.

Option 1: Fix the Regex #

If you still want to use regex, adjust the pattern to target only the content after the last backslash:

import re
txt = r'C:\Users...\Standard Loadflows Seq and Dyn PSSEv34 - 2019-02-20\AutumnHi-20180531-183047-34-SystemNormal\AutumnHi-20180531-183047-34-SystemNormal.sav'
result = re.findall(r'\\([^\\]+)\.sav$', txt)
print(result[0])  # Outputs: AutumnHi-20180531-183047-34-SystemNormal.sav

Let's break this down:

• [^\\]+: Matches one or more characters that are not backslashes (so it stops at the last backslash)
• \.sav$: Ensures we're matching the .sav at the very end of the string (the $ anchors it to the end)
• The parentheses capture just the filename we want

Option 2: Use Python's Built-in Path Tools (Recommended!) #

Regex is overkill for path handling — Python has standard libraries that handle all edge cases (like different OS path separators, trailing slashes, etc.) automatically.

Using os.path (works in all Python 3 versions):

import os
txt = r'C:\Users...\Standard Loadflows Seq and Dyn PSSEv34 - 2019-02-20\AutumnHi-20180531-183047-34-SystemNormal\AutumnHi-20180531-183047-34-SystemNormal.sav'
filename = os.path.basename(txt)
print(filename)  # Outputs the exact filename you need

Using pathlib (modern, object-oriented approach for Python 3.4+):

Since you're using Python 3.7, pathlib is a great choice:

from pathlib import Path
txt = r'C:\Users...\Standard Loadflows Seq and Dyn PSSEv34 - 2019-02-20\AutumnHi-20180531-183047-34-SystemNormal\AutumnHi-20180531-183047-34-SystemNormal.sav'
filename = Path(txt).name
print(filename)

Both of these methods will reliably give you the final filename without having to mess with regex patterns.

内容的提问来源于stack exchange，提问作者Rick Zhang