CODEWITHSUNDEEP
regex
JP Martinez
JP Martinez

Reputation: 35

Regex nested asterisk

I found this regular expression in an old system i'm working on. 

(\s*)*

I'm pretty sure the extra " * " at the end is redundant but I want to make sure is not doing anything before I remove it. It's causing a performance issue when it's used in the regex.matches() method to the point that hangs the entire system if the string used as a parameter has 25+ spaces

Does anybody knows if that particular syntax has a special functionality?

Ps: Its a pretty huge system so I can't test every posible scenario

Upvotes: 2

Views: 272

Answers (2)

Mitya
Mitya

Reputation: 34556

Assuming the inner * is greedy, then, yes, I think the outer one is redundant. The outer * attempts to repeat the sub-match, but there would only ever be one instance of the sub-match because it's greedy.

Upvotes: 1

Alex W
Alex W

Reputation: 38183

It is redundant. You can just use multiple matches to capture 0 or more groups of spaces, which is what the extra asterisk is specifying.

Upvotes: 1

Related Questions