Regular Expressions 101

Pro

^start of line

Non-Capturing Group(?:\b(?:, ?)?(Apple|Bat|Car)\b(?!.*?\b\1\b)){3}

{3}repeats the group contents below exactly 3 times:

\ban ASCII word boundary

Non-Capturing Group(?:, ?)?

?repeats the group contents below at most once:

,the literal , (44₁₀ / 54₈ / 2C₁₆)

?optionally matches the literal (32₁₀ / 40₈ / 20₁₆)

Group 1(Apple|Bat|Car)

1st AlternativeApple

Applethe literal text Apple (case insensitive)

2nd AlternativeBat

Batthe literal text Bat (case insensitive)

3rd AlternativeCar

Carthe literal text Car (case insensitive)

\ban ASCII word boundary

Negative Lookahead(?!.*?\b\1\b)

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

\ban ASCII word boundary

\1the text saved by group 1

\ban ASCII word boundary

$end of line

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

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

Detailed match information will be displayed here automatically.

25 tokens

^(?:\b(?:, ?)?(Apple|Bat|Car)\b(?!.*?\b\1\b)){3}$

New

Bat, Car, Apple
Car, Bat, Apple
Apple, Car, Bat
Apple, Car, Bat, Stick
Bat, Car
Apple

Bat, Car, Apple
Car, Bat, Apple
Apple, Car, Bat
Apple, Car, Bat, Stick
Bat, Car
Apple