Regular Expressions 101

Pro

Group 1((\d+){4})

Group 2(\d+){4}

{4}repeats the group contents below exactly 4 times:

\d+a digit, repeated at least once

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\1the text saved by group 1

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.

25 tokens

((\d+){4})-\1

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