Regular Expressions 101

^start of string

Negative Lookahead(?!.*(?=(.))((.{9})+|(.(?!(?3)*$))+|(?>.(?!(...)*$)|(.(?!(.{27})*$)){7})+)\1)

.*any character (except for line terminators), repeated any number of times

Positive Lookahead(?=(.))

Group 1(.)

.any character (except for line terminators)

Group 2((.{9})+|(.(?!(?3)*$))+|(?>.(?!(...)*$)|(.(?!(.{27})*$)){7})+)

1st Alternative(.{9})+

Group 3(.{9})+

+repeats the group contents below at least once:

.{9}any character (except for line terminators), repeated exactly 9 times

2nd Alternative(.(?!(?3)*$))+

Group 4(.(?!(?3)*$))+

+repeats the group contents below at least once:

.any character (except for line terminators)

Negative Lookahead(?!(?3)*$)

(?3)*calls group 3 as a subroutine, repeated any number of times

$end of string, or before its final line terminator

3rd Alternative(?>.(?!(...)*$)|(.(?!(.{27})*$)){7})+

Atomic Group(?>.(?!(...)*$)|(.(?!(.{27})*$)){7})+

+repeats the group contents below at least once:

1st Alternative.(?!(...)*$)

.any character (except for line terminators)

Negative Lookahead(?!(...)*$)

Group 5(...)*

*repeats the group contents below any number of times:

.any character (except for line terminators)

$end of string, or before its final line terminator

2nd Alternative(.(?!(.{27})*$)){7}

Group 6(.(?!(.{27})*$)){7}

{7}repeats the group contents below exactly 7 times:

.any character (except for line terminators)

Negative Lookahead(?!(.{27})*$)

Group 7(.{27})*

*repeats the group contents below any number of times:

.{27}any character (except for line terminators), repeated exactly 27 times

$end of string, or before its final line terminator

\1the text saved by group 1

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

^(?!.*(?=(.))((.{9})+|(.(?!(?3)*$))+|(?>.(?!(...)*$)|(.(?!(.{27})*$)){7})+)\1)

New

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