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python - 如何构造正则表达式来检查有效路径？

问题描述

我正在尝试为下面的路径构建正则表达式。你能帮我为它构建正则表达式吗？

path  = "root-dir/document/2018/02/29/14/02-sample.txt"
pattern = '((a-z)+(-)(a-z)+/(a-z)+/(\d{4})/(\d{2})/(\d{2})/(\d{2})/(\d{2)(-)(a-z)+(.)(a-z)+)'
bool(re.match(pattern,path))

"root-dir/document/2015/01/25/13/01-sample.txt" //this should be accepted
"root-dir/2015/01/25/13/01-sample.txt" //this should not be accepted
"root-dir/document/201/01/25/13/01-sample.txt" //this should not be accepted as 201 part should be 4 digit
"root-dir/document/2015/01/2/13/01-sample.txt" //this should be not accepted as 2 part should be 2 digit
"root-dir/document/2015/01/25/13/sample.txt" //this should not be accepted as the last part should be something like this 03-sample.txt

标签： pythonregex

解决方案

您的模式几乎没有问题，正确的用法是：

import re
pattern = r'([a-z]+(-)[a-z]+/[a-z]+/(\d{4})/(\d{2})/(\d{2})/(\d{2})/(\d{2})(-)[a-z]+(\.)[a-z]+)'
print(bool(re.match(pattern,path))) #True

您的模式'((a-z)+(-)(a-z)+/(a-z)+/(\d{4})/(\d{2})/(\d{2})/(\d{2})/(\d{2)(-)(a-z)+(.)(a-z)+)'不起作用，因为：

  • \d{2)-你应该关闭{not})
  • a-z- 这相当于里面的任何小写字母，而且只有在里面[ ]不是( )
  • .\.-如果你的意思是字符.（ASCII：46），你应该使用它，因为re它表示任何不是换行符的字符，还记得使用原始字符串而不是普通字符串

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