Regular Expressions 101

Pro

^start of line

Group 1([^;,\n]*)

Negated Character Class[^;,\n]*

*matches any number of characters outside the set below:

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

,the literal , (44₁₀ / 54₈ / 2C₁₆)

\na line-feed (newline) character (ASCII 10)

Group 2(;.*(\1)(,.*|;)?|;;)

1st Alternative;.*(\1)(,.*|;)?

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

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

Group 3(\1)

\1the text saved by group 1

Group 4(,.*|;)?

?repeats the group contents below at most once:

1st Alternative,.*

,the literal , (44₁₀ / 54₈ / 2C₁₆)

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

2nd Alternative;

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

2nd Alternative;;

;;the literal text ;;

$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

Detailed match information will be displayed here automatically.

25 tokens

Regular Expression

^([^;,\n]*)(;.*(\1)(,.*|;)?|;;)$

New

/foo;/foo,/bar,/test;
/foo;/bar,/foo,/test;
/foo;/bar,/test,/foo;
/foo;/bar,/baz,/test;
/foo;;/foo,/bar,/test
/foo;;/bar,/foo,/test
/foo;;/bar,/test,/foo
/foo;;/bar,/baz,/test
/foo;;

Substitution

/foo;/foo,/bar,/test;
/foo;/bar,/foo,/test;
/foo;/bar,/test,/foo;
/foo;/bar,/baz,/test;
/foo;;/foo,/bar,/test
/foo;;/bar,/foo,/test
/foo;;/bar,/test,/foo
/foo;;/bar,/baz,/test
/foo;;