Regular Expressions 101

Pro

^start of line

Character Class[a-z]

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

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 _ (95₁₀ / 137₈ / 5F₁₆)

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

*repeats the group contents below any number of times:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

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 _ (95₁₀ / 137₈ / 5F₁₆)

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 _ (95₁₀ / 137₈ / 5F₁₆)

$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.

25 tokens

^[a-z][a-z0-9_]*(\.[a-z0-9_]+)*[a-z0-9_]*$

New

a
ab
ab_
a.b
a._
a.1
a_0.b
a_0.b_
a_._
a.1._
a._.1
a.1.b
a.b._
java.awt.event


.
..
.g
.1
1.
._
_.
0
0a
_1
_a
a.b.
a.
a.0.
a._.
javax.swing.JFrame