Regex match everything after a certain character (b) except a another character (closing curly brace)

Question

Problem:

I have a string, {aabb.1234} - those curly brackets are included. I'm trying to make a regex to match everything after the second b except that last closed curly bracket } . In other words, I need to match a period and everything after it.

What I've tried:

So far I have the first part, which identifies everything after the second b : \.[^.]+$ , but I'm at a loss on how to make the } an exception. Thoughts?

Edit: I'm planning to use this regex inside R 's gsub function. If that makes a difference in your suggestions.

Answer 1

Match the last curly bracket with a non capturing group and what you want with a normal group. You can then access your desired string with group #1 of each match.

(\.[^.]+)(?:})$

here is a working example

Edit per the question update:

It works with R, as well, note group #1 of the match. See here at regexr.

Answer 2

You may use the following regex pattern:

(?<=[^b]b).*?(?=\}|$)

Demo

Here is an explanation of the regex pattern:

(?<=[^b]b)  assert that what precedes is the first b (itself preceded by a non b)
.*?         then match all content until reaching
(?=\}|$)    a } or the end of the input

Answer 3

You need a sub like

sub('.*\\.([^}]+).*', '\\1', '{aabb.1234}')

See the R online demo and the regex demo . Note that gsub replaces all occurrences, while sub replaces the first one, and sub is enough since here, the whole string is matched, and replaced with a backreference to Group 1.

Details :

• .* - zero or more chars, as many as possible
• \. - a dot (it is double escaped in the R string literal, as \ is used to form string escape sequences, such as "\n" (a line feed char, etc.)
• ([^}]+) - Group 1: any one or more chars other than a } char ( [^...] is a negated bracket expression in a TRE regex)
• .* - zero or more chars, as many as possible (the rest of the string)

The \1 in the replacement refers to the value of Group 1.