Regex problem, matches the whole string instead of a part

Question

I have this string:

(3 + 5) * (1 + 1)

I want to match this strings:

(3 + 5)

and

(1 + 1)

I used this to try to match it:

(\(.*\))

But that matches the whole string, from the first ( to the last ).

Any idea on how to fix this / make it working?

Answer 1

Use a non-greedy match, ie

(\(.*?\))

Answer 2

If you don't care about nested parenthesis, use

(\([^()]*\))
#  ^^^^^

to avoid matching any ( or ) inside a group.

Answer 3

How about

([^*]+)

Answer 4

There are two ways to look at this:

• Instead of greedy repetition *, I want reluctant *?
  • i.e. (\(.*?\))
• Instead of ., I want [^)], i.e. anything but )
  • i.e. (\([^)]*\))

Note that neither handles nested parentheses well. Most regex engine would have a hard time handling arbitrarily nested parantheses, but in .NET you can use balancing groups definition.

Related questions

• Difference between .*? and .* for regex
• How can I exclude some characters from a class?

References

• regular-expressions.info/Character class and Repetition