Regular Expressions 101

Positive Lookbehind(?<=^|, )

1st Alternative^

^start of line

2nd Alternative,

, the literal text ,

\ban ASCII word boundary

Non-Capturing Group(?:dog|cat)

1st Alternativedog

dogthe literal text dog (case sensitive)

2nd Alternativecat

catthe literal text cat (case sensitive)

\ban ASCII word boundary

Positive Lookahead(?=$|,)

1st Alternative$

$end of line

2nd Alternative,

,the literal , (44₁₀ / 54₈ / 2C₁₆)

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

(?<=^|, )\b(?:dog|cat)\b(?=$|,)

New

dog, cat
dog, dog, cat
dog, dog, dog
dog, dog, dog, cat
dog, dog, dog, dog, cat
dog, dog, dog, dog, dog
dog, dog, dog, dog, dog, cat
dog, dog, dog, dog, dog, dog, dog, cat
dog, dog, dog, dog, dog, dog, dog, dog, dog