正则表达式：匹配连续的标点符号并替换为第一个

Question

I am trying to remove some predefined consecutive punctuation marks and replace them with the first. Thus:

1. us, -> us
2. us -> us
3. us! -> us
4. hiiii!!!, -> hiiii!

I tried the following code:

import re
r = re.compile(r'([.,/#!$%^&*;:{}=-_`~()])*\1')
n = r.sub(r'\1', "ews by almalki : Tornado, flood deaths reach 18 in U.s., more storms ahead ")
print(n)

Answer 1

You just need to capture the first punctuation mark and match the rest:

([.,/#!$%^&*;:{}=_`~()-])[.,/#!$%^&*;:{}=_`~()-]+

See the regex demo

Note that the - must be put at the end (or start) of the character class in order not to create a range (or it can be escaped inside the character class).

Details :

• ([.,/#!$%^&*;:{}=_`~()-]) - capturing group with the punctuation symbols you defined
• [.,/#!$%^&*;:{}=_`~()-]+ - 1+ punctuation symbols

Python demo :

import re
r = re.compile(r'([.,/#!$%^&*;:{}=_`~()-])[.,/#!$%^&*;:{}=_`~()-]+')
n = r.sub(r'\1', "ews by almalki : Tornado, flood deaths reach 18 in U.s., more storms ahead ")
print(n)