匹配首次出现的非字母数字字符的正则表达式

Question

I am parsing some user input to make a basic Discord bot assigning roles and such. I am trying to generalize some code to reuse for different similar tasks (doing similar things in different categories/channels).

Generally, I am looking for a substring (the category), then taking the string after as that categories value. I am looking line by line for my category, replacing the "category" substring and returning a stripped version. However, what I have now also replaces any space in the "value" string.

Originally the string looks like this:

Gamertag : 00test gamertag

What I want to do, is preserve the spaces in the value. The regex I am trying to do is: match all non alpha-numeric chars until the first letter.

My return is already matching non alpha but can't figure out how to get just first group, looks like it should be simply adding a? to make it a lazy operator but not sure.. example code and string below (regex I want to replace is the final print string).

String I am working with:

- 00test Gamertag      #(or any non-alpha delimiter)

Desired Results (by matching and stripping the extra characters)

00test Gamertag     #(remove leading space and any non-alpha characters before the first words)

The regex I am trying to do is: match all non alpha-numeric chars until the first letter. Should be something like the following, which is close to what I use to strip non-alphas now but it does all not the first group - so I want to match the first group of non-alphas in a string to strip that part using re.sub..

\W+?

https://www.online-python.com/gDVhZrnmlq

Thank you!

Answer 1

It depends on your inputs, you can use two regex to achieve your goal, the first to remove all non alpha-numeric from your string including the ones between words, and the second one to remove whitespaces between words if there is more than one space between each two words:

import re


gamer_tag = "µ& - 00test          -   Gamertag"
gamer_tag = re.sub(r"[^a-zA-Z0-9\s]", "", gamer_tag)
gamer_tag = re.sub(r" +", " ", gamer_tag)
print(gamer_tag.strip())

# Output: 00test Gamertag

You can remove the second re.sub() if you sure that there will no more than one space between words.

gamer_tag = "- 00test Gamertag "
gamer_tag = re.sub(r"[^a-zA-Z0-9\s]", "", gamer_tag)
print(gamer_tag.strip())

# Output: 00test Gamertag

Answer 2

Your regex will substitute the non-alphanumerical characters anywhere in the input string. If you only need to have this happening at the start of the string, then use the start-of-input anchor (ie ^ ):

^\W+