Regular Expressions 101

Pro

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

Group 1(.)

.any character (except for line terminators)

Negative Lookahead(?!\1)

\1the text saved by group 1

Group 2(.)

.any character (except for line terminators)

\2the text saved by group 2

\1the text saved by group 1

Non-Capturing Group(?:(?!\])|(?<!\[.{4}))

1st Alternative(?!\])

Negative Lookahead(?!\])

\]the literal ] (93₁₀ / 135₈ / 5D₁₆)

2nd Alternative(?<!\[.{4})

Negative Lookbehind(?<!\[.{4})

\[the literal [ (91₁₀ / 133₈ / 5B₁₆)

.{4}any character (except for line terminators), repeated exactly 4 times

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

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

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27 tokens

.*?(.)(?!\1)(.)\2\1(?:(?!\])|(?<!\[.{4})).*

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