Regular Expressions 101

Explanation

Pro

^start of line

Group 1((\d)\2(?!.+\2)){2}

{2}repeats the group contents below exactly 2 times:

Group 2(\d)

\da digit

\2the text saved by group 2

Negative Lookahead(?!.+\2)

.+any character (except for line terminators), repeated at least once

\2the text saved by group 2

Group 3(\d)

\da digit

\3{3}the text saved by group 3, repeated exactly 3 times

$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.

25 tokens

^((\d)\2(?!.+\2)){2}\2(\d)\3{3}$

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