Regular Expressions 101

Pro

1st Alternative(?P<a_only>^a)

Group a_only(?P<a_only>^a)

^start of string

athe literal a (97₁₀ / 141₈ / 61₁₆) (case insensitive)

2nd Alternative(?:a:)(?P<a_colon>[^\/].+)

Non-Capturing Group(?:a:)

a:the literal text a: (case insensitive)

Group a_colon(?P<a_colon>[^\/].+)

Negated Character Class[^\/]

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

.+any character (except for line terminators), repeated at least once

3rd Alternative(?P<a_slash>a\/\d{1,2})

Group a_slash(?P<a_slash>a\/\d{1,2})

athe literal a (97₁₀ / 141₈ / 61₁₆) (case insensitive)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

\d{1,2}a digit, repeated between 1 and 2 times

Global pattern flags

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

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

Detailed match information will be displayed here automatically.

25 tokens

(?P<a_only>^a)|(?:a:)(?P<a_colon>[^\/].+)|(?P<a_slash>a\/\d{1,2})

New

a
a:example.com
a:mailers.example.com
a/24
a:offsite.example.com/24

a
a:example.com
a:mailers.example.com
a/24
a:offsite.example.com/24