Regular Expressions 101

Pro

^start of line

Group 1(\d)

\da digit

Negative Lookahead(?!(?:\1|-)*$)

Non-Capturing Group(?:\1|-)*

*repeats the group contents below any number of times:

1st Alternative\1

\1the text saved by group 1

2nd Alternative-

-the literal - (45₁₀ / 55₈ / 2D₁₆)

$end of line

\d*a digit, repeated any number of times

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

*repeats the group contents below any number of times:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\d+a digit, repeated at least once

$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.

27 tokens

^(\d)(?!(?:\1|-)*$)\d*(?:-\d+)*$

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