Java Regex space or beginning of parenthesis

Question

I am trying to write some regex such that:

100 pages and 100pages (either "100 pages match" or " 100 pages" match. The 2nd contains a space before the token "100"

(100 pages and (100pages

but not

1100 pages , 1,100 pages etc.

I'm currently using Java regex.

What I've come up with is (\\s){1}(100)(\\s){0,1}(pages)

but cannot incorporate the initial parenthesis. Hopefully I can use the | logical operator to make my regex lean. Any suggestions?

Answer 1

You could use a regex like this :

[\(\s]100\s?pages

It will first match an open parenthesis or space ( [\\(\\s] ), followed by 100 , followed by an optional space ( \\s? ), followed by pages .

Answer 2

So you want to match 100 pages and 100pages but not 1100pages or 1,100 pages right and you dont want the ( in regex?

Try this https://regex101.com/r/5uOlup/1

(?<!\d|\d,)100\s?pages