Regular Expressions 101

Pro

^start of line

\.?optionally matches the literal . (46₁₀ / 56₈ / 2E₁₆)

Non-Capturing Group(?:\d+|[a-z]+)

1st Alternative\d+

\d+a digit, repeated at least once

2nd Alternative[a-z]+

Character Class[a-z]+

+matches at least one character from the set below:

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

Non-Capturing Group(?:\.(?:\d+|[a-z]+))*

*repeats the group contents below any number of times:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Non-Capturing Group(?:\d+|[a-z]+)

1st Alternative\d+

\d+a digit, repeated at least once

2nd Alternative[a-z]+

Character Class[a-z]+

+matches at least one character from the set below:

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

\.?optionally matches the literal . (46₁₀ / 56₈ / 2E₁₆)

$end of line

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.

27 tokens

^\.?(?:\d+|[a-z]+)(?:\.(?:\d+|[a-z]+))*\.?$

a.1.b.c.d.2.a
a.1.b.c.d.2.777
.a.1.b.c.d.2.777
3423.a.1.b.c.d.2.2342345
a.2.b.c2.a.1.
aha.comment.1.app
aha.comment1.app