Question

我正在研究ATBS第9章的“ fillingGaps”项目。该项目如下：编写一个程序，该程序在单个文件夹中查找所有具有给定前缀的文件，例如spam001.txt，并查找编号中的任何空白（例如spam001.txt和spam003.txt，但没有spam002.txt）。让程序重命名所有以后的文件以弥补这一空白。

我试图定义一个正则表达式，该正则表达式忽略文件名的第一部分，并主要通过仅标识以.txt结尾且以.txt开头的文件，重点关注传递给“搜索”的路径中的文本文件。两位数。（我的文件格式为“ Capitalsquiz1.txt”至“ Capitalsquiz35.txt”，“ Capitals_answers1.txt”至“ Capitals_answers35.txt”，文件夹路径中还有其他文件类型）。


import os, re

# Define regular expression to identify files of given prefix

sequence = re.compile(r'''(.*?) # text preceeding the number prefix
                      (\d{1|2})  # followed by one or two digits
                      ('.txt')$  # ends with '.txt'
                      ''', re.VERBOSE)


# Define folder path to search

search = input('Please enter folder to search:')

filenames = list(os.walk(search))[0][2] # os.walk returns tuple of three lists(Foldername,subfolders, filenames). List converts it to list of three lists.
                                        # [0][2] picks out the third list (filenames)[2] within the main list (the one that contains all three)[0].

filename = ''.join(filenames)


filename = ''.join(filenames)
text = sequence.search(filename)
skan = text.group(0)
print(text)


# Search for the files that match the regular expression

# Loop through files to identify gaps

正则表达式似乎不起作用，但我不明白为什么。它不断返回“无”

  File "C:\Users\peada\Documents\Python\Automate the Boring Stuff\Chapter 9\fillingGaps.py", line 28, in <module>
    skan = text.group(0)
AttributeError: 'NoneType' object has no attribute 'group'```

Any help that helps me learn where I went wrong appreciated. I could lookup a solution in minutes but that's pointless.

为什么在连续字符串中搜索正则表达式返回“ None”？

0 个答案: