regex101: JavaScript Match Workspace

Pro

Negative Lookahead(?!.?C.?C)

.?optionally matches any character (except for line terminators)

Cthe literal C (67₁₀ / 103₈ / 43₁₆) (case sensitive)

.?optionally matches any character (except for line terminators)

Cthe literal C (67₁₀ / 103₈ / 43₁₆) (case sensitive)

Group 1([ABC]{3})

Character Class[ABC]{3}

{3}matches exactly 3 characters from the set below:

Athe literal A (65₁₀ / 101₈ / 41₁₆) (case sensitive)

Bthe literal B (66₁₀ / 102₈ / 42₁₆) (case sensitive)

Cthe literal C (67₁₀ / 103₈ / 43₁₆) (case sensitive)

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

26 tokens

Regular Expression

(?!.?C.?C)([ABC]{3})

New

Find 3 characters together.
All of the characters must be from the group 'ABC'
0 to 3 of them can be 'A'
0 to 3 of them can be 'B'
0 to 1 of them can be 'D'
In which case the following would match:

ABC ACB CBA BCA AAB ABA BAA AAC ACA CAA ABB BAB BBA BBB

and the following would not match:

CCC CCA CAC ACC CCB CBC BCC

Substitution

Find 3 characters together.
All of the characters must be from the group 'ABC'
0 to 3 of them can be 'A'
0 to 3 of them can be 'B'
0 to 1 of them can be 'D'
In which case the following would match:

ABC ACB CBA BCA AAB ABA BAA AAC ACA CAA ABB BAB BBA BBB

and the following would not match:

CCC CCA CAC ACC CCB CBC BCC