How to extract substrings that contain parenthesis with regexp()-CodePudding

I am trying to extract substrings that come before either a left parenthesis or a dot with regexp(). For example

example1='qwer(1).asdf; qwer(1).zxcv;';

example2='qwer.asdf; qwer.zxcv;';

I tried

expression='(?<varname>.*?)(\(\d \)){?}.';

expression='(?<varname>.*?)(?<others>\(\d \)){?}.';

expression='(?<varname>.*?)\(';

expression='(?<varname>.*?)(';

expression='(?<varname>.*?)/(';

with

parts=regexp(example1,expression,'names');

None worked.

How exactly does matching with parenthesis work in regexp()?

The official documentation doesnt mention how to characters that form operators, quantifiers, etc.

CodePudding user response：

You can use

example1 = '01/11/2000  20-02-2020  03/30/2000  16-04-2020';
expression = '(?<varname>\w )[(.]';
parts=regexp(example1,expression,'names');

See the regex demo. Details:

(?<varname>\w ) - Group "varname": one or more word chars
[(.] - a ( or . char.

CodePudding user response：

/(?<varname>(\S*?)(?:\(.*?;)|(\S*?)(?:\..*?;))/g

Here's an illustration of parentheses in regex below. I added the above to actually answer your question

 /\(.*?\)/g

This will match the parentheses and everything between for each

The \ escapes the parenthesis, the *? matches the smallest amount so it doesn't match everything between the first and last parentheses and the global flag does it for each occurrence

https://regex101.com/ is a great resource