Regular Expressions 101

Pro

1st Alternative^(?:(?![ad];).*\R*)*

^start of line

Non-Capturing Group(?:(?![ad];).*\R*)*

*repeats the group contents below any number of times:

Negative Lookahead(?![ad];)

Character Class[ad]

athe literal a (97₁₀ / 141₈ / 61₁₆) (case sensitive)

dthe literal d (100₁₀ / 144₈ / 64₁₆) (case sensitive)

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

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

\R*a newline sequence, repeated any number of times

2nd Alternative^([ad];.*(?:\R[ad];.*)*)(?(?![\s\S]*\R[ad];)\R*)

^start of line

Group 1([ad];.*(?:\R[ad];.*)*)

Character Class[ad]

athe literal a (97₁₀ / 141₈ / 61₁₆) (case sensitive)

dthe literal d (100₁₀ / 144₈ / 64₁₆) (case sensitive)

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

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

Non-Capturing Group(?:\R[ad];.*)*

*repeats the group contents below any number of times:

\Ra newline sequence

Character Class[ad]

athe literal a (97₁₀ / 141₈ / 61₁₆) (case sensitive)

dthe literal d (100₁₀ / 144₈ / 64₁₆) (case sensitive)

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

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

Condition(?(?![\s\S]*\R[ad];)\R*)

Uses the first branch if the lookaround matches

Negative Lookahead(?![\s\S]*\R[ad];)

Character Class[\s\S]*

*matches any number of characters from the set below:

\sany whitespace character

\Sany non-whitespace character

\Ra newline sequence

Character Class[ad]

athe literal a (97₁₀ / 141₈ / 61₁₆) (case sensitive)

dthe literal d (100₁₀ / 144₈ / 64₁₆) (case sensitive)

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

If the condition is true, match this branch:\R*

\R*a newline sequence, repeated any number of times

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

^(?:(?![ad];).*\R*)*|^([ad];.*(?:\R[ad];.*)*)(?(?![\s\S]*\R[ad];)\R*)

New


a;; z
toy;d;hh 
toy
;b;;jj
z;
d;23
d;23td
;;io;
b y;b;12
z
a;b;bb;;;34
z

Substitution

$1


a;; z
toy;d;hh 
toy
;b;;jj
z;
d;23
d;23td
;;io;
b y;b;12
z
a;b;bb;;;34
z