Regular Expressions 101

Non-Capturing Group(?:(\b)|\B)

1st Alternative(\b)

Group 1(\b)

\ban ASCII word boundary

2nd Alternative\B

\Bnot an ASCII word boundary

Negative Lookahead(?!\k{char})

\k{char}the text saved by group char

Group anything(?<anything>.)

.any character (except for line terminators)

Group char(?<char>[a-z])

Character Class[a-z]

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

\k{char}++the text saved by group char, repeated at least once

Condition(?(1)\B)

Uses the first branch if group 1 matched

If the condition is true, match this branch:\B

\Bnot an ASCII word boundary

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.

Search reference

Regular Expression

(?:(\b)|\B)(?!\k{char})(?<anything>.)(?<char>[a-z])\k{char}++(?(1)\B)

New

test ajjjo new
here bbb cca
here abbbbbc x
test jjka