Regular Expressions 101

Pro

Non-Capturing Group(?:(?<=;)|(?<=^))

1st Alternative(?<=;)

Positive Lookbehind(?<=;)

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

2nd Alternative(?<=^)

Positive Lookbehind(?<=^)

^start of line

Group 1([^;]+)

Negated Character Class[^;]+

+matches at least one character outside the set below:

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

Positive Lookahead(?=.*;\1(?=;|$))

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

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

\1the text saved by group 1

Positive Lookahead(?=;|$)

1st Alternative;

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

2nd Alternative$

$end of line

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

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

(?:(?<=;)|(?<=^))([^;]+)(?=.*;\1(?=;|$));

New

AC;AC MR;TA;AC MR;AC;AC MR;TA;SDA
AB;QQ;AB QQ;CD;EF
AB;AB;AB QQ;CD;EF

AC;AC MR;TA;AC MR;AC;AC MR;TA;SDA
AB;QQ;AB QQ;CD;EF
AB;AB;AB QQ;CD;EF