Regular Expressions 101

^start of line

Negative Lookahead(?!.*[AB] (?:and|&))

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

Character Class[AB]

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

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

the literal (32₁₀ / 40₈ / 20₁₆)

Non-Capturing Group(?:and|&)

1st Alternativeand

andthe literal text and (case sensitive)

2nd Alternative&

&the literal & (38₁₀ / 46₈ / 26₁₆)

Negative Lookahead(?!.*(?:and|&) [AB])

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

Non-Capturing Group(?:and|&)

1st Alternativeand

andthe literal text and (case sensitive)

2nd Alternative&

&the literal & (38₁₀ / 46₈ / 26₁₆)

the literal (32₁₀ / 40₈ / 20₁₆)

Character Class[AB]

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

Bthe literal B (66₁₀ / 102₈ / 42₁₆) (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

Detailed match information will be displayed here automatically.

25 tokens

Regular Expression

^(?!.*[AB] (?:and|&))(?!.*(?:and|&) [AB])

New

A and B
A B
B and A
A B and C
& B

A and B
A B
B and A
A B and C
& B