检查字符串是否匹配正则表达式的前 n 个字符

Question

I have a python site built in Django where a user will be uploading files that they may or may not have permission to add. The permissions are created through a series of regex patterns (there is over 1000). At one point in my site I have a place for the user to view their permissions (using a search filter and a list). However what I want to do is if the user types in a string and the string matches any part of each regular expression. I want it in the list.

Right now I have if(filter.match(pattern)) { //add pattern to list } I have also tried searching instead of matching.

An example of what I am looking for:

If I have a list of regex patterns:

^(12345678)\.(txt)$
^(qwertyuiop)\.(txt)$
^(qwerty)\.(txt)$
^(23456)\.(txt)$

if the user were to enter qwert the list would show ^(qwertyuiop)\.(txt)$ and ^(qwerty)\.(txt)$ , whereas if the user entered qwertyu the list would only show ^(qwertyuiop)\.(txt)$ . Similarly if the user entered 234 the list would show ^(12345678)\.(txt)$ and ^(23456)\.(txt)$ but if the user entered 1 the list would only show ^(12345678)\.(txt)$ .

Is it possible to accomplish this? If so how would I manage it?

Thanks for the Help!

Answer 1

re.search should work for this. By the sound of it you're not too picky with users entering arbitrary strings that could crash your server. If so you could just do this.

import re

patterns = [
    r"^(12345678)\.(txt)$",
    r"^(qwertyuiop)\.(txt)$",
    r"^(qwerty)\.(txt)$",
    r"^(23456)\.(txt)$",
]

filter = re.compile("qwert")
filtered_patterns = [p for p in patterns if filter.search(p)]