Regular Expressions 101

Non-Capturing Group(?:(?:www?).)?

?repeats the group contents below at most once:

Non-Capturing Group(?:www?)

wwthe literal text ww (case sensitive)

w?optionally matches the literal w (119₁₀ / 167₈ / 77₁₆) (case sensitive)

.any character (except for line terminators)

\ba Unicode word boundary

Group 1((xn--)?[a-z0-9]+(-[a-z0-9]+)*\.)+

+repeats the group contents below at least once:

Group 2(xn--)?

?repeats the group contents below at most once:

xn--the literal text xn-- (case sensitive)

Character Class[a-z0-9]+

+matches at least one character from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

0-9one character from 0 (48₁₀) to 9 (57₁₀)

Group 3(-[a-z0-9]+)*

*repeats the group contents below any number of times:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Character Class[a-z0-9]+

+matches at least one character from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

0-9one character from 0 (48₁₀) to 9 (57₁₀)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Character Class[a-z]{2,}

{2,}matches at least 2 characters from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

\ba Unicode word boundary

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

No unit tests · Add a test to get started

27 tokens

Regular Expression

(?:(?:www?).)?\b((xn--)?[a-z0-9]+(-[a-z0-9]+)*\.)+[a-z]{2,}\b

There are no unit tests, click to add some.