Regular Expressions 101

Explanation

Pro

1st Alternative(?sx) \bblue\b(?=.*(bleu))

(?sx)applies the following effective flags to the remainder of the pattern: gsx

s modifier: single line. Allows a dot to match line terminators

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

\ban ASCII word boundary

bluethe literal text blue (case sensitive)

\ban ASCII word boundary

Positive Lookahead(?=.*(bleu))

.*any character, repeated any number of times

Group 1(bleu)

bleuthe literal text bleu (case sensitive)

2nd Alternative \bred\b(?=.*(rouge))

\ban ASCII word boundary

redthe literal text red (case sensitive)

\ban ASCII word boundary

Positive Lookahead(?=.*(rouge))

.*any character, repeated any number of times

Group 2(rouge)

rougethe literal text rouge (case sensitive)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

s modifier: single line. Allows a dot to match line terminators

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

Detailed match information will be displayed here automatically.

25 tokens

(?sx)
\bblue\b(?=.*(bleu))
|
\bred\b(?=.*(rouge))

New

blue cheese, a red nose.
bleu rouge

blue cheese, a red nose.
bleu rouge