Regular Expressions 101

^start of line

Group 1(-?\d+)

-?optionally matches the literal - (45₁₀ / 55₈ / 2D₁₆)

\d+a digit, repeated at least once

Non-Capturing Group(?:$(\d+(?:\(\d+$)*)?\))?

?repeats the group contents below at most once:

\(the literal ( (40₁₀ / 50₈ / 28₁₆)

Group 2(\d+(?:$\d+$)*)?

?repeats the group contents below at most once:

\d+a digit, repeated at least once

Non-Capturing Group(?:$\d+$)*

*repeats the group contents below any number of times:

\(the literal ( (40₁₀ / 50₈ / 28₁₆)

\d+a digit, repeated at least once

\)the literal ) (41₁₀ / 51₈ / 29₁₆)

Non-Capturing Group(?:$(\d+(?:\(\d+$)*)?\))?

?repeats the group contents below at most once:

\(the literal ( (40₁₀ / 50₈ / 28₁₆)

Group 3(\d+(?:$\d+$)*)?

?repeats the group contents below at most once:

\d+a digit, repeated at least once

Non-Capturing Group(?:$\d+$)*

*repeats the group contents below any number of times:

\(the literal ( (40₁₀ / 50₈ / 28₁₆)

\d+a digit, repeated at least once

\)the literal ) (41₁₀ / 51₈ / 29₁₆)

$end of line

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

^(-?\d+)(?:\((\d+(?:\(\d+\))*)?\))?(?:\((\d+(?:\(\d+\))*)?\))?$

New

4
4(2(3))
4(2(3)(1))
4(2(3)(1))(6(5))
-4(2(3)(1))(6(5))