Regular Expressions 101

^start of line

Non-Capturing Group(?:\w+://)?

?repeats the group contents below at most once:

\w+any word character, repeated at least once

://the literal text ://

Group 1((?:[^./?#]+\.)?([^/?#]+))

Non-Capturing Group(?:[^./?#]+\.)?

?repeats the group contents below at most once:

Negated Character Class[^./?#]+

+matches at least one character outside the set below:

.the literal . (46₁₀ / 56₈ / 2E₁₆)

/the literal / (47₁₀ / 57₈ / 2F₁₆)

?the literal ? (63₁₀ / 77₈ / 3F₁₆)

#the literal # (35₁₀ / 43₈ / 23₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Group 2([^/?#]+)

Negated Character Class[^/?#]+

+matches at least one character outside the set below:

/the literal / (47₁₀ / 57₈ / 2F₁₆)

?the literal ? (63₁₀ / 77₈ / 3F₁₆)

#the literal # (35₁₀ / 43₈ / 23₁₆)

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.

Search reference

Regular Expression

^(?:\w+://)?((?:[^./?#]+\.)?([^/?#]+))

New

https://api.twitter.com/blog/category/2?user=42&status=enabled
abc.xyz.com/blog/category/2?user=42&status=enabled
https://abc.xyz.com/blog/category/2?user=42&status=enabled
abc.xyz.com/blog/category/2?user=42&status=enabled
http://localhost