I need a regular expression to use in python that captures one group containing the whole string minus the last 2 characters, but if the string have a "-" , then ignore it and all after it.

Ex:

abcde = abc

jklmno-pqrs = jklm

I think it would be a mix between (.*)..$ and ^([^-]*) , but I dont know how to combine them.

CodePudding user response：

You could use a capture group matching any char except - followed by matching 2 chars other than -

^([^-\n] )[^-\n]{2}(?:-.*)?$

In parts, the pattern matches:

• ^ Start of string
• ([^-\n] ) Capture group 1, match 1 or more chars other than - (add \n to not match a newline)
• [^-\n]{2} Match 2 chars other than -
• (?:-.*)? Optionally match - followed by 0 times any char
• $ End of string

Regex demo

For example

import re
 
pattern = r"^([^-\n] )[^-\n]{2}(?:-.*)?$"
s = ("abcde\n""jklmno-pqrs")
 
print(re.findall(pattern, s, re.M))

Output

['abc', 'jklm']

CodePudding user response：

You can combine two regex using pipe delimiter like this

re.findall('(.*)..$|^([^-]*)', string)

for reference '|' pipe delimiter is used for grouping multiple regular expressions