Regular Expressions 101

Explanation

Pro

Non-Capturing Group(?:(?<subdomain>[a-z0-9\.\-]*)\.)?

?repeats the group contents below at most once:

Group subdomain(?<subdomain>[a-z0-9\.\-]*)

Character Class[a-z0-9\.\-]*

*matches any number of characters 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)

\-the literal - (45₁₀ / 55₈ / 2D₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Group domain(?<domain>(?!com)[a-z0-9\-]{3,}(?=\.[a-z\.]{2,}))

Negative Lookahead(?!com)

comthe literal text com (case sensitive)

Character Class[a-z0-9\-]{3,}

{3,}matches at least 3 characters 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 - (45₁₀ / 55₈ / 2D₁₆)

Positive Lookahead(?=\.[a-z\.]{2,})

\.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)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Non-Capturing Group(?:(?<tld>[a-z\.]{2,})$)

Group tld(?<tld>[a-z\.]{2,})

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)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

$end of line

Global pattern flags

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

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

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

Match Information

Detailed match information will be displayed here automatically.

Quick Reference

25 tokens

Regular Expression

(?:(?<subdomain>[a-z0-9\.\-]*)\.)?(?<domain>(?!com)[a-z0-9\-]{3,}(?=\.[a-z\.]{2,}))\.(?:(?<tld>[a-z\.]{2,})$)

New

apple.orange.banana.clevername.co.uk
strawberry.apple.orange.banana.clevername.co.uk
tangerine.com.au
simple.com
bit.ly
something.bit.ly
clevername.com.au
hello.world.ninja
www.something.cancerresearch